STAT 110 - Homework #4 (20 pts
STAT 110 - Homework #4 (20 pts.) (DUE WEDNESDAY, MAY 24th)
1.) The admissions office claims that the mean cost of books for students at Winona State University is $250.00 per semester. Based on data that was collected by one of my statistics courses a few years ago we have the following summary information regarding the cost of books for students per semester.
|Sample Mean |[pic]269.3389 |
|Sample Std Dev |s = 91.9895 |
|Sample Size |n = 239 |
a) Do these data provide sufficient evidence that the mean cost of books for students per semester at WSU exceeds $250.00? Be sure to justify your conclusion and show all your work! (4 pts.)
b) Construct and interpret a 95% CI for the mean book cost per semester for WSU students. (4 pts.)
2.) Hypertension is defined as a blood pressure over 140 mmHg systolic and/or over 90 mmHg diastolic. Hypertension, if not corrected, can cause long-term health problems. In the college-age population (18-24 years of age), about 9.2% have hypertension. Suppose that a blood donor program is occurring in a college dormitory during finals week. Before each student gives blood, the nurse takes a blood pressure reading. Of 196 donors, it was found that 29 have hypertension. Do these data indicate that the population proportion of students with hypertension during final exams week is higher than 9.2%? Justify your answer. (4 pts.)
3.) A study of 200 rainbow trout caught on a baited size 8 barbed hooks and released with the line cut at the hook (but the hook not removed from the fish) showed that 58 fish died. Find and interpret a 95% confidence interval for the proportion of all rainbow trout that die when caught and released using the described method. (4 pts.)
4.) In 1960, census results indicated that the age at which American men first married had a mean of 23.3 years. It is widely suspected that young people today are waiting longer to get married. Investigators wanted to find out if the mean age of first marriage has increased during the past 40 years. A sample of n = 40 men who married for the first time last year was taken. The men in this sample married at an average age of 24.2 years with a standard deviation of 5.3 years. Is there evidence the mean age that men are first getting married has increased when compared to the 1960 figure? (4 pts.)
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