hypotheses 2

1. A firm that produces light bulbs claims that their lightbulbs last 1500 hours, on average. You wonder if the average might differ from the 1500 hours that the firm claims. To explore this possibility you take a random sample of n = 25 light bulbs purchased from this firm and record the lifetime (in hours) of each bulb. You then conduct an appopriate test of hypothesis. Some of the information related to the hypothesis test is presented below.
Test of H0: = 1500 versus H1: 1500
Sample mean 1509.5
Std error of mean 4.854
Assuming the life length of this type of lightbulb is normally distributed, what is the p-value associated with this test?

2. A medical doctor wishes to test the claim that the standard deviation of the systolic blood pressure of deep sea divers is less than 450. To do so, she selected a random sample of 20 divers and found s = 432.
Assuming that the systolic blood pressures of deep sea divers are normally distributed, if the doctor wanted to test her research hypothesis at the .01 level of significance, what is the critical value?

3. The ABC battery company claims that their batteries last 100 hours, on average. You decide to conduct a test to see if the company’s claim is true. You believe that the mean life may be different from the 100 hours the company claims. You decide to collect data on the average battery life (in hours) of a random sample of n = 20 batteries. Some of the information related to the hypothesis test is presented below.
Test of H0: = 100 versus H1: 100
Sample mean 98.5
Std error of mean 0.777
Assuming the life length of batteries is normally distributed, what is the p-value associated with this test?

4. Suppose a firm that produces light bulbs wants to know whether it can say that its light bulbs typically last more than 1500 hours. Hoping to find support for their claim, the firm collects a random sample of n = 25 light bulbs and records the lifetime (in hours) of each bulb. The information related to the hypothesis test is presented below.
Test of H0: 1500 versus H1: > 1500
Sample mean 1509.5
Std error of mean 4.854
What is the test value that you would use to conduct this test? Place your answer, rounded to 3 decimal places in the blank.

5. Sample evidence is statistically significant at the level only if the p–value is larger than .

6. The hypothesis that an analyst is trying to prove is called the

7. A type II error occurs when: