STA 2023 Work sheet #12
Do the indicated hypothesis test for each. Give Ho, Ha, one-tail or two-tail, critical value, calculated value (round to the same number of places as the critical value from the table), decision, and conclusion statement. DRAW EACH !!
1) Test
the claim that for the population of statistics final exams the mean score is
given by m
= 75. Sample data are n = 100, 
, and 
. Use a = .05.
2) Test
the claim that the population of college sophomores has a mean GPA greater than
2.25. Sample statistics include n = 150, 
and 
, using a = .02.
3) Test
the claim that for the population of trigonometry final exams, the mean score
is m
= 75. A sample has n = 20, and 
. Use a = .05.
4) Test
the claim that the population of college sophomores has a mean GPA less than
2.55. A sample has n = 24, 
and 
. Use a = .05.
5) A sample of 40 tablets of a night-time cold medication has mean amount of acetaminophen of 593 mg. with a standard deviation of 21 mg. Use a = .01 to test the manufacturer’s claim that m = 600 mg.
6) When 5 BMW cars are crashed under standard conditions, the repair costs, in dollars, are: 797 571 904 1147 418
Use a = .05 to test the claim that the mean for all BMW’s is less than $1000.
7) Previous tests of new baseballs had a mean bounce height of 92.64 inches. In a test of 50 balls, the mean bounce height was 92.47 inches and the standard deviation was 1.68 inches. Use a = .05 to test the claim that the mean of the new balls is 92.64.
8) This list shows the birth weights, in kilograms, for male babies born to women taking a special vitamin supplement.
3.73 4.37 3.73 4.33 3.39 3.68 4.68 3.52
3.02 4.09 2.47 4.13 4.47 3.22 3.43 2.54
With a = .05 test the claim that the mean birth weight for all male babies of mothers given these vitamins is greater than the mean for the population of all males 3.35 kg.