3.  About 13% of the United States population is left-handed.  Suppose that a researcher speculates that individuals with schizophrenia are more likely to be left-handed than the US population.  The researcher surveys 104 individuals with schizophrenia and finds that 22 of them are left-handed.  Based on this sample, is there enough evidence that the population proportion of individuals with schizophrenia who are left-handed is more than the 13% (or 0.13).  Construct and interpret a 95% confidence interval for the population proportion of individuals with schizophrenia who are left-handed. (b) What is the sample size (n) for the confidence interval?

5.  Is the number of games won by a major league baseball team in a season related to how many runs the team scored for the season?  The table below shows the runs scored (x) and the number of games won (y) for a sample of teams from the 2025 season. X (Runs Scored)    849    798    825    806    793 Y (Number of Games Won)    94    94    93    97    92 Find the equation of the regression line using the least squares approach.  You may use the results of your calculator’s LinReg procedure. (a) What is the name of b0 ? 

13.  Consider the following discrete probability distribution. X 3 5 7 9 11 P(X) 0.5 0.2 0.1 0.1 0.1 (c)  Find the mean of this discrete probability distribution.  (Round your answer to one decimal place).

5.  Is the number of games won by a major league baseball team in a season related to how many runs the team scored for the season?  The table below shows the runs scored (x) and the number of games won (y) for a sample of teams from the 2025 season. X (Runs Scored)    849    798    825    806    793 Y (Number of Games Won)    94    94    93    97    92 Find the equation of the regression line using the least squares approach.  You may use the results of your calculator’s LinReg procedure. (a) What is b0 ? (Round your answer to threen decimal places.)

12.  The probability of giving birth to twins for women who take the fertility drug gonadotropins is 0.30 (or 30%).  Assume that the probability of giving birth to twins for women taking gonadotropins remains constant from woman to woman.  Consider a DIFFERENT random sample of 10 pregnant women who have taken gonadotropins. (e)  What is the probability that no more than 2 pregnant women who have taken gonadotropins will give birth to twins?  (Use the TI-83 Plus to help you find the answer.) 

10.  Students enrolled in Mr. H’s STA2023 course took a survey during the Summer A 2026 semester at SF.  Results are summarized as follows (given in proportions): Have you ever smoked marijuana? Yes No Totals Do you vape daily? Yes 0.09 0.04 0.13 No 0.52 0.35 0.87 Totals 0.61 0.39 1.00   (c)  What is the probability that a student vapes daily or has ever smoked marijuana?

5.  Is the number of games won by a major league baseball team in a season related to how many runs the team scored for the season?  The table below shows the runs scored (x) and the number of games won (y) for a sample of teams from the 2025 season. X (Runs Scored)    849    798    825    806    793 Y (Number of Games Won)    94    94    93    97    92 Find the equation of the regression line using the least squares approach.  You may use the results of your calculator’s LinReg procedure. (b) What is b1 ? (Round your answer to three decimal places.)

7.  A survey suggests that 13% of students vape daily, while 68% exercise regularly.  Furthermore, 5% of students vape daily and exercise regularly.  Based on this given information, fill in the remaining boxes of the following table (boxes labeled a, b, c, d, e and f). Note:  based on some information above, some boxes have been filled in for you. Do you vape daily? Yes No Totals Do you exercise regularly? Yes (a) (b) 68% No (c) (d) (e) Totals 13% (f) 100%   (e)  Fill in the percentage that belongs in box (e) above.

10.  A random sample of weight in pounds of SF students taking STA2023 during the Summer 2026 semester is given below:      Males:  140  150  135  178  208  176  197  169  166      Females:  138  126  143  115  105  125  130  112  136  134  137 (c) What is the maximum weight for females?

6.  Disney World’s Animal Kingdom is a family theme park in Orlando, Florida. One of its longest rides, “Kilimanjaro Safaris,” has a ride time that is normally distributed with a mean of μ = 14 minutes and a standard deviation of σ = 3 minutes.  If the ride lasts more than 18.5 minutes, it is considered too long and the manager must decrease the ride time. (a)  What is the probability that it takes a park guest more than 18.5 minutes to complete the “Kilimanjaro Safaris” ride?