1:Suppose Exam 1 has a normal distribution and the top 15% of students have grades above 88. If the mean is 79, find the standard deviation.

Round your answer to whole number.

2Compare the 3 data sets:

Data A: 34, 52, 72, 85, 62

Data B: 10, 11, 9, 8, 10

Data C: 190, 185, 194, 192, 186

Which of the data sets has the largest center?

Which of the data sets has the smallest spread?

Group of answer choices

A has the largest center and A has the smallest spread

C has the largest center and C has the smallest spread.

C has the largest center and B has the smallest spread.

B has the largest center and B has the smallest spread.

B has largest center and A has the smallest spread.

3

What percent of the observations in a distribution lie between 1^st quartile and maximum?

4Ten years ago 53% of Americans families owned stocks or stock funds. An investment company collected a random sample of 300 American families and found that 46% of the families own stocks or stock funds. Is this enough to claim that the population proportion of American families own stocks or stock funds has decreased over the years at 5% level?

a. Calculate the test statistic.

Answer: . Write your answer in 2 decimals.

b. Find the p-value.

Answer: . Write your answer in 4 decimals.

c. Is this enough to claim that the population proportion of American families own stocks or stock funds has decreased over the years at 5% level?

Answer: . Write 1 for YES and 2 for NO

5Suppose a random sample of 27 students at a college are taking an average of 14.2 units and standard deviation of 2.6 units. Construct a 95% confidence interval for the average number of units for all the students in the college.

a. Find the critical value.

Answer: . Write your answer in 3 decimals.

b. Calculate the margin of error.

Answer: . Write your answer in 2 decimals.

c. Write the interval.

Answer: ( , ). Write your answer in 2 decimals.

6

Given the frequency table.

Grades	frequency
A	11
B	15
C	7
D	4
F	?

a. If n = 40, how many students got grade F on the exam? Answer is

b. What percentage of students passed the exam? Answer is %. Round answer to 1 decimal. Ex. 12.35%, write 12.4 in the box

7:Given the 5-Number Summary: 12, 21, 24, 25, 34

Construct the interval to determine the outliers.

Write (Lower Bound, Upper Bound) of the interval.

Answer is ( , )

8:The length of human pregnancies from conception to birth varies according to a distribution that is approximately Normal with mean 266 days and standard deviation 18 days. Find the percentage of the pregnancies fall between 260 days and 290 days?

Group of answer choices

a:0.7215

b:0.4759

c:0.4116

d:0.5956

e:0.5375

9:The distribution of hours of sleep per week night, among college students, is found to be Normally distributed, with a mean of 6.5 hours and standard deviation of 0.8 hours. The percentage of college students that sleep at least 8 hours per night is about

Group of answer choices

a:0.1056

b:0.8944

c:0.6628

d:0.0301

e:0.9699