Questions and Answers of Basic Statistics In Business And Economics 10th

After computing the correlation coefficient r from 50 pairs of data, you find that r = 0. Does it follow that there is no relationship between the two variables? Why or why not?
Use the scatterplot for life expectancy and infant mortality in Figure 4.Data From Figure 4:- Frequency 20 15 10 10 5 2 3 4 5 6 Mean hours on Internet searches
Describe three trends shown in Figure 20. The Ever-Growing Presence of Women in Summer Olympics Women participating 44.4% 5,000 42.3% 40.7 4,500 38.2 Percentage of women participants -Total number of
In testing a claim about a population mean, a larger z test statistic always results in a larger P-value.Decide whether the statement makes sense (or is clearly true) or does not make sense (or is
In testing the claim that the mean IQ score of statistics students is greater than 100, the alternative hypothesis is expressed as μ > 100.Decide whether the statement makes sense (or is clearly
A significance level of 0.05 indicates that the probability of making a type I error is 0.05.
A handy mnemonic for interpreting the P-value in a hypothesis test is this: “If the P (value) is low, then the null must go.”
Ha: μ ≠2.55, n = 100, x̄ = 2.58, σ = 0.29.Find the value of the standard score, z, and determine whether the alternative hypothesis is supported at a 0.05 significance level.
Ha: μ ≠156.2, n = 225, x̄ = 155.5, σ = 29.Find the value of the standard score, z, and determine whether the alternative hypothesis is supported at a 0.05 significance level.
Ha: μ ≠0.88, n = 50, x̄ = 0.75, σ = 0.18.Find the value of the standard score, z, and determine whether the alternative hypothesis is supported at a 0.05 significance level.
Ha: μ ≠877, n = 90, x̄ = 921, σ = 52.Find the value of the standard score, z, and determine whether the alternative hypothesis is supported at a 0.05 significance level.
z = -0.4 for Ha: μ < 25 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
z = -2.4 for Ha: μ < 727 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
z = 1.9 for Ha: μ > 36.25 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
z = 1.5 for Ha: μ > 0.227 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
z = -1.6 for Ha: μ ≠ 0.389 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
z = -2.0 for Ha: μ ≠ 172 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
z = 1.9 for Ha: μ ≠ 25.7 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
z = 2.7 for Ha: μ > 19.4 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
z = 3.5 for Ha: μ > 75 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
z = -2.1 for Ha: μ < 1007 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
z = 1.1 for Ha: μ < 149.6 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
z = 0.15 for Ha: μ ≠ 90.3 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
z = 3.5 for Ha: μ ≠ 1022 Find the P-value that corresponds to the standard z-score, and determine whether the alternative hypothesis is supported at the 0.05 significance level.
H0: The patient is free of a particular disease.Ha: The patient has the disease.Without using the terms “null hypothesis” and “alternative hypothesis,” identify the type I error and identify
H0: The defendant is not guilty.Ha: The defendant is guilty.Without using the terms “null hypothesis” and “alternative hypothesis,” identify the type I error and identify the type II error.
H0: The lottery is fair.Ha: The lottery is biased.Without using the terms “null hypothesis” and “alternative hypothesis,” identify the type I error and identify the type II error.
Using a search engine such as Google, search for “power” of a hypothesis test. Describe what the power of a hypothesis test is.
What do p, p̂, and P-value represent?
In conducting a hypothesis test as described in this section, which term best describes the particular distribution that is used: uniform, normal, probability, weighted?
In a test of the claim that a majority of Americans favor registration of all handguns, the null hypothesis is p = 0.5 and the alternative hypothesis is p > 0.5.Decide whether the statement makes
In a two-tailed hypothesis test of a claim about a proportion, the P-value is the area to the right of the standard score, z.Decide whether the statement makes sense (or is clearly true) or does not
The claim of p < 0.25 can never be supported if the sample proportion p̂ is greater than 0.25.Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly
Find a news article or research report that describes (perhaps not explicitly)a hypothesis test for a population proportion.Attach the article and summarize the method used.
In each case, identify the population parameter about which a claim is made, state the null and alternative hypotheses for a hypothesis test, and indicate whether the hypothesis test will be
For each of the three cases from Example 1, describe the possible outcomes of a hypothesis test and how we would interpret these outcomes.Data From Example 1:-In each case, identify the population
Consider the Gender Choice example in which the sample size is n = 100 and the sample proportion is p̂ = 0.64. Using techniques that we will discuss later in this chapter, it is possible to
You suspect that a coin may have a bias toward landing tails more often than heads, and decide to test this suspicion by tossing the coin 100 times. The result is that you get 40 heads (and 60
In the United States, the average car is driven about 12,000 miles each year. The owner of a large rental car company suspects that for his fleet, the mean distance is greater than 12,000 miles each
Assuming that the null hypothesis is true and the mean starting salary for Columbia College graduates is $39,000, is it statistically significant to find a sample in which the mean is only$37,000?
Recall the case of the rental car fleet owner who suspects that the mean annual mileage of his cars is greater than the national mean of 12,000 miles. He selects a random sample of n = 225 cars and
Consider the study in which University of Maryland researchers measured body temperatures in a sample of n = 106 healthy adults, finding a sample mean body temperature of x̄ = 98.20 F with a sample
Consider the null hypothesis from Example 3—that mean body temperature equals 98.6 F(H0: μ = 98.6oF).a. What correct decisions are possible with this null hypothesis?b. Explain the meaning of
The success of precious metal mines depends on the purity (or grade) of ore removed and the market price for the metal. Suppose the purity of gold ore must be at least 0.5 ounce of gold per ton of
Suppose the national unemployment rate is 9.5%. In a survey of n = 450 people in a rural Wisconsin county, 54 people are found to be unemployed. County officials apply for state aid based on the
A random sample of n = 750 people is selected, of whom 92 are left-handed. Use these sample data to test the claim that 10% of the population is left-handed.
Pollsters often use randomly selected digits between 0 and 9 to generate parts of telephone numbers to be called. What is the distribution of such randomly selected digits? If we repeat the process
When a random sample is used to estimate a population mean, the sample mean tends to become a better estimate of the population mean as the sample size increases.
Based on a random sample of hospital costs for car crash victims, the sample mean is $$9,004$ and the margin of error for a 95% confidence interval is $$266$.Identify the confidence interval.
For the confidence interval given in Exercise 1, we can interpret that result by saying that “95% of sample means will fall between 8.0518 grams and 8.0902 grams.”Decide whether the statement
When sample data are used to estimate the value of a population mean, the margin of error decreases as the sample size increases.Decide whether the statement makes sense (or is clearly true) or does
sample size = 49, sample mean = 25.2 cm, sample standard deviation = 2.2 cm Assume that population means are to be estimated from the samples described. In each case, use the sample results to
Sample size = 81, sample mean = 4.5 km, sample standard deviation = 3.1 km Assume that population means are to be estimated from the samples described. In each case, use the sample results to
n = 100, x̄ = 8.0 ft, s = 2.0 ft Assume that population means are to be estimated from the samples described. In each case, use the sample results to approximate the margin of error and 95%
Margin of error = $$5$, standard deviation = $$20$
Margin of error = 18.2 cm, standard deviation = 95.2 cm
Margin of error = 3.5 ml, standard deviation = 155.2 ml
Margin of error = 0.5 g, standard deviation = 8.7 g
The Wechsler IQ test is designed so that the mean is 100 and the standard deviation is 15 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of Delaware
An economist wants to estimate mean annual income from the first year of work for college graduates who have had the profound wisdom to take a statistics course. How many such incomes must be found
All of the major television networks conduct regular polls on a variety of issues. Visit the Web site of at least one major network and gather the results of a particular poll that involves
Here is a typical statement made by the media: “Based on a survey of 1050 likely voters, 44% plan to vote for the Republican candidate, and this survey has a margin of error of 3 percentage
We can interpret the confidence interval given in Exercise 1 by saying that there is a 95% chance that the true population proportion will fall between 0.393 and 0.553.Decide whether the statement
The Kingston Chronicle publishes an article stating that, based on survey results, 82% of Orange County residents oppose an increase in the sales tax, with a margin of error of 4 percentage points. A
E = 0.04.Estimate the minimum sample size needed to achieve the given margin of error.
E = 0.05.Estimate the minimum sample size needed to achieve the given margin of error.
Repeat Exercise 17 assuming that the sample size is doubled to 10,000. Given that the large cost and effort of conducting the Nielsen survey would be doubled, does this increase in sample size appear
Visit the Nielsen Media Research Web site and report on the actual methods used to estimate population proportions and confidence intervals in Nielsen ratings.
Texas has roughly 225,000 farms, more than any other state in the United States. The actual mean farm size is μ = 582 acres, and the standard deviation is σ = 150 acres. For random samples of n =
Consider the distribution of sample proportions shown in Figure 5.Suppose you randomly select the following sample of 32 responses:Compute the sample proportion, p̂, for this sample. How far does it
Figure 9 shows a histogram for a random sample of n = 264 women (drawn from the same NHANES III study used for the sample of men in Figure 6). The mean of these data is x = 59.6 grams and the
A study conducted by the Garbage Project at the University of Arizona analyzed the contents of garbage discarded by n = 62 households; the households ranged in size from 2 to 11 members. The
A study by University of Maryland researchers investigated the body temperatures of n = 106 subjects. The sample mean of the data set is x = 98.20oF and the standard deviation for the sample is s =
You want to study housing costs in the country by sampling recent house sales in various( representative) regions. Your goal is to provide a 95% confidence interval estimate of the housing cost.
The Bureau of Labor Statistics finds 5,160 unemployed people in a sample of n = 60,000 people. Estimate the population unemployment rate and give a 95% confidence interval.
The Nielsen ratings for television use a random sample of households. A Nielsen survey results in an estimate that a women’s World Cup soccer game had 72.3% of the entire viewing audience.Assuming
The Gallup Organization conducted a survey of 1,016 randomly selected adults who were asked:Among those surveyed, 59% believed that Pete Rose should be eligible. Find the margin of error and
You plan a survey to estimate the proportion of students on your campus who carry an iPad regularly. How many students should be in the sample if you want (with 95% confidence) a margin of error of
A poll by Yankelovich Partners concluded that 61% of all households have a computer, with a margin of error of 3.5 percentage points. Approximately what sample size must have been used in this poll?
What is a hypothesis test?
What is a P-value for a hypothesis test?
In a test of the claim that, among patients treated with Ziac, the proportion who experience dizziness is less than 0.06, the null hypothesis is ρ = 0.06.
In interpreting a P-value of 0.001, a researcher states that the results are statistically significant because the P-value is very small, indicating that the results are not likely to occur by chance.
Package labeling indicates that Twix candy bars have an amount of caloric content equal to 250 calories.Formulate the null and alternative hypotheses for a hypothesis test. State clearly the two
A high school principal claims that the mean SAT score of seniors at his school is less than the national average of 1518.Formulate the null and alternative hypotheses for a hypothesis test. State
The Chief Operations Officer of a medical facility claims that treatments can increase the probability that a baby will be a girl so that the proportion of girls is greater than 0.7.Formulate the
The quality control manager at a manufacturing company claims that the proportion of defective carbon monoxide detectors is less than 0.04.Formulate the null and alternative hypotheses for a
A sales representative claims that her vending machines dispense coffee so that the mean amount supplied is equal to 10 ounces.Formulate the null and alternative hypotheses for a hypothesis test.
The Food and Drug Administration claims that a pharmaceutical company is producing aspirin tablets with a mean amount of aspirin that is less than 350 milligrams.Formulate the null and alternative
A high school teacher claims that the majority of her students do not know what the term Holocaust refers to.Formulate the null and alternative hypotheses for a hypothesis test. State clearly the two
An educator claims that less than 20% of college graduates smoke.Formulate the null and alternative hypotheses for a hypothesis test. State clearly the two possible conclusions that address the given
When analyzing paired sample data, the value of the correlation coefficient r allows us to determine whether one variable has a direct causal effect on the other.For Exercises 5–8, decide whether
A variable can have a direct causal effect on another variable only if the correlation coefficient is given by r = 1.For Exercises 5–8, decide whether the statement makes sense (or is clearly true)
A study showed that there is a correlation between exposure to second-hand smoke and the measured amount of cotinine in the body. We can establish that exposure to second-hand smoke is a cause of
When the body absorbs nicotine, it converts it into cotinine. Experiments have ruled out coincidence as an explanation for a correlation between exposure to second-hand smoke and cotinine in the
Test grades are affected by the amount of time and effort spent studying and preparing for the test.For Exercises 9–12, determine whether the stated causal connection is valid. If the causal
People with higher resting pulse rates (beats per minute) tend to have higher IQ scores.For Exercises 9–12, determine whether the stated causal connection is valid. If the causal connection appears
There is a strong correlation between tobacco smoking and incidence of lung cancer, and most physicians believe that tobacco smoking causes lung cancer. Yet, not everyone who smokes gets lung cancer.
Several things besides smoking have been shown to be probabilistic causal factors in lung cancer. For example, exposure to asbestos and exposure to radon gas, both of which are found in many homes,
Those who favor gun control often point to a positive correlation between the availability of handguns and murder rates to support their position that gun control would save lives. Does this

Showing 1 - 100 of 786