Question 1

Gotham City is piloting a crime reduction program so that it does not have to rely on the help of super-heroes anymore. The table below shows the number of crimes committed every year (since 2005). The mayor of Gotham needs your help and you are tasked to find the following:

Years ()	2005	2006	2007	2008	2009	2010	2011	2012	2013	2014
Crimes ()	1369	1346	1340	1330	1327	1314	1326	1314	1302	1306

Use the data to create an appropriate linear function (in equation form) that represents the number of crimes as a function of the calendar year. Also, give the and 2 values from your calculator. Regression Equation: = 2 = Round all values to 3 decimal places. Gotham can stop relying on super-heroes' help once the number of crimes drop below 600 per year. In which year will that happen?

Question 2

An unknown metal has been found and the following experimental results have been tabulated in the table below. The table contains the grams of the unknown metal and the volume in milliliters of water displacement. Find a linear model that express volume as a function of the mass. Round your answers to 3 decimal places

grams	Volume in ml
19	197.3
20.5	215
22	230.8
23.5	241.6
25	264.9
26.5	280.8
28	293.7

Volume = + where x is the grams of the unknown metal

Question 3

Test the claim that the mean GPA of night students is smaller than 2.6 at the .10 significance level. The null and alternative hypothesis would be:0:=2.6 1:2.6 0:=2.6 1:<2.6 0:=0.65 1:>0.65 0:=2.6 1:>2.6 0:=0.65 1:0.65 0:=0.65 1:<0.65

The test is:

left-tailed right-tailed two-tailed Based on a sample of 20 people, the sample mean GPA was 2.57 with a standard deviation of 0.04 The test statistic is: (to 2 decimals) The critical value is: (to 2 decimals) Based on this we:

• Fail to reject the null hypothesis
• Reject the null hypothesis

Question 4

Fayech University claims that the mean GPA of night students is approximately normally distributed with mean 2.5 with a population standard deviation of 0.05.

We wish to test the claim that the mean GPA of night students is larger than 2.5 at the 0.05 significance level.

Based on a sample of 55 people, we find the sample mean GPA was 2.52. The null and alternative hypothesis would be:

0:=2.5 1:2.5 0:=2.5 1:<2.5 0:=2.5 1:>2.5 0:=2.5 1:>2.5 0:=2.5 1:2.5 0:=2.5 1:<2.5

The test is:

left-tailed two-tailed right-tailed

We should use a:

• t-test for the mean
• z-test for the mean
• z-test for the proportion The test statistic is: (to 2 decimals) The p-value is: (to 2 decimals) Based on this we:
• Reject the null hypothesis
• Fail to reject the null hypothesis

Question 5

The state of CT claims that the average time on death row is 15 years. A random survey of 75 death row inmates revealed that the average length of time on death row is 17.5 years with a standard deviation of 5.5 years. Conduct a hypothesis to test the state of CT's claim. What type of test should be run?

• t-test of a mean
• z-test of a proportion

The alternative hypothesis indicates a

• two-tailed test
• right-tailed test
• left-tailed test
• Calculate the p-value. What is the decision?
• We reject the claim that the average time on death row is 15 years
• We fail to reject the claim that the average time on death row is 15 years

Question 6

In a survey, 19 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $33 and standard deviation of $6. Construct a confidence interval at a 90% confidence level. Give your answers to one decimal place.

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Question 7

We wish to estimate what percent of adult residents in a certain county are parents. Out of 500 adult residents sampled, 30 had kids. Based on this, construct a 95% confidence interval for the proportion, p, of adult residents who are parents in this county. Give your answers as decimals, to three places. < p <

Question 8

A confidence interval for the population mean number of US states Americans have visited was found to be 11.8 to 12.9. Find the midpoint of this confidence interval:

Question 9

Suppose the age that children learn to walk is normally distributed with mean 13 months and standard deviation 1.3 month. 8 randomly selected people were asked what age they learned to walk. Round all answers to 4 decimal places where possible.

a) what is the probability of one randomly selected learned to walk when the person was between 12 and 13.5 months old

b)For the 8 people find the average age that the learned to walk is between 12 and 13.5 months old.

c)For part b, is the assumption that the distribution is normal necessary? yes or no

d) find the IQR for the average first time walking age for groups of 8 people. Round to two decimal places.

QI =----- months

Q3= ---- months

IQR=------ months

Please answer these questions sequentially. Thanks