1. MATH 2311
Review for Exam 2

2. A density curve consists of two line segments, going from (0,0) to (1,1) and from (1,1) to (1.5,1). What is the probability of being above x=1?

3. The weight of persons of a certain age is normally distributed with a mean of 160 pounds and a standard deviation of 15 pounds. What range of weights should the middle 68% contain?

4. If X is normally distributed with a mean of 150 and a standard deviation of 15, what is P(X>155)?

5. Find the value of c so that P(Z>c) = 0.32.

6. A sample of 60 data points is selected from a population with mean of 140 and variance of 13. Determine the mean and standard deviation for the sample.

7. A sample of 25 iron filaments is selected from a large population with a mean weight of 1 gram and a standard deviation of 0.1 grams. What is the probability that the sample will have a mean weight of more than 1.2 grams?

8. In a large city, 75% of adults drive to work
In a large city, 75% of adults drive to work. A sample of 50 adults are selected. What is the mean and standard deviation of this sample? What is the probability that the sample has less than 30 people drive to work>?

9. Determine the correlation coefficient for the following data table:

10. Determine the equation of the LSRL for the table of data:

11. Determine the residual for the x-value, x = 6 from the table.

12. Plot the residuals of the table:

13. Based on the two-way table describing car-type to driver’s age, determine what percent of year olds drive pick up trucks.

14. Describe Convenience Sampling

15. What type of sampling is used here: The customer service score of a store is determined by the results of a survey attached the bottom of the store receipt.

16. People’s height is given by a normal probability with a mean of 70 inches and a standard deviation of 3 inches.
Sketch the normal distribution curve, label the heights of each standard deviation, label the major percents of the population.
Determine the z-score of a person with a height of 64 inches.
Determine what height someone would be if they are in the 75th percentile of heights.

17. Base your answers to the following on the table comparing age and average commuting distance.
Construct a scatter plot
Find the LSRL
Interpret the slope
Find the correlation coefficient
Find the coefficient of determination
Find the residual value for a person in their 40s.
Construct the residual plot
Is this a good model for this data?

18. Use a random digit table to simulate the following experiment: An organization (consisting of 60% men and 40% women) is selecting 10 people to be part of a planning committee. Tell how you would assign men/women to numbers in the random number table. Use the first line in the table to simulate a group of 10 people. Does this group match the general demographics of the organization?