1. A normal distribution can be characterized as a/an _____ distribution.

A. bell-shaped B. symmetric C. asymptotic D. all of these

2. The following are characteristics of a normal curve except for three. Determine which of the following are not characteristic of a normal curve. I. The mode and median occur at .

II. The curve is symmetric about the vertical axis through the mean .

III. The normal curve is asymptotic to the vertical axis on both sides.

IV. The total area under the curve and above the vertical axis is equal to 1.

V. The probability that the normal random variable is equal to a specific discrete value is always zero, since the normal random variable is continuous.

VI. The probability that the normal random variable is between two values is given by the area under the curve between the two given values and the vertical axis.

A. VI,I,II B. III,IV,VI C. I,V,II D. II,IV,VI

3. Standardization allows a researcher to

A. locate where a score falls in a distribution and describe how it compares to other scores in the distribution.

B. identify whether data entry errors have been made.

C. "normalize" their data.

D. compare their data to SAT scores.

4. The mean amount spent by a family of four on food per month is $500 with a standard deviation of $75. Assuming that the food costs are normally distributed, what is the probability that a family spends less than $410 per month?

A. 0.2158 B. 0.8750 C. 0.0362 D. 0.1151

5. The value of the standard deviation of the standard normal distribution is

A. 1.0 B. 0.5 C. 0.0 D. 1.0

6. If a computed z value is zero, then the value of the normal random variable must be _____ the mean.

A. greater than B. equal to C. less than D. not equal to

7. An advertising agency would like to create an advertisement for a fast food restaurant claiming that the average waiting time from ordering to receiving your order is less than 5 minutes. The agency measured the time from ordering to serving of order for 25 customers and found that the average time was 4.7 min with a standard deviation of 0.6 min. The appropriate set of hypotheses to be tested is

A. ???????? : ???? 4.7 ????????. ????????: ???? 4.7.

B. ???????? : ???? 5 ????????. ????????: ????

C. ???????? : ???? 4.7 ????????. ????????: ????

D. ???????? : ???? 5 ????????. ????????: ???? 5.

8. A student wanted to test whether there was a difference in the average daily hours of study for students living in four different dormitories. She selected a random sample of 50 students from each of the four dormitories. What is the null hypothesis for this situation?

A. The mean daily hours of study is 3 hours for the four dormitories.

B. The mean daily hours of study is the same for the four dormitories.

C. The mean daily hours of study is different for each of the 200 students in the sample.

D. The mean daily hours of study is not the same for all four dormitories.

9. If we are trying to establish that the mean of population 1 is greater than the mean of population 2, the appropriate set of hypotheses is

A. ???????? : ????1 ????2 0 vs ????????: ????1 ????2 0

B. ???????? : ????1 ????2 0 vs ????????: ????1 ????2

C. ???????? : ????1 ????2 = 0 vs ????????: ????1 ????2 0

D. ???????? : ????1 ????2 0 vs ????????: ????1 ????2 0

For numbers 10-13: The maximum oxygen uptake of healthy women is assumed to be thirty. Thirty women in a mountain city were measured and the following values were found: mean is 33.3 and standard deviation is 12.14. Can we hypothesize at a 0.05 level of significance that these women have a higher oxygen uptake than thirty?

10. What test statistic should be used in testing the hypotheses?

A. z-statistic for single mean

B. t-statistic for equal variances

C. t-statistic for paired difference

D. t-statistic for single mean

11. What is the computed value of the test statistic?

A. 1.489 B. 0.00 C. 1.489 D. 15.00

12. What is the critical value?

A. 1.645 B. 1.96 C. 1.699 D. 1.697 13.

13.What would be your decision concerning the null hypothesis?

A. Reject the null hypothesis.

B. There is insufficient data to make a decision

C. Do not reject the null hypothesis

D. Either A or B

For numbers 14-17: A study was conducted using 50 mobile network users, who volunteered to participate in the research as the entry of the third player in the country is on its way. One of the items studied was the average connection speed in the last month. Based on the data in the following table, is there differences between the connectivity speed of the two networks for the past month? Use 5% level of significance. Assume equal variances.

Speed (Mbps) Mobile Network A Mobile Network B Mean 8.2 5.6 Standard Deviation 5.9 5.7 Number of students 20 30