Chapter 9 Means and Proportions Hypothesis Tests



Download 12.66 Kb.
Date23.05.2017
Size12.66 Kb.
#19021
Name ________________________________ Date ___________________
Chapter 9 – Means and Proportions Hypothesis Tests

1. A certain tobacco company advertised that its cigarettes contain at most 40 mg of nicotine, but a researcher doubts this claim. The researcher tests 10 randomly selected cigarettes and found the nicotine levels given below.



47.3

39.3

40.3

38.3

46.3

43.3

42.3

49.3

40.3

46.3

Test, at a 0.01 significance level, to see whether there is significant evidence that the cigarettes contain more than 40 mg of nicotine.

2. According to official census figures, 8% of couples living together are not married. A researcher took a random sample of 400 couples and found that 9.5% of them are not married. Test at the 15% significance level if the current percentage of unmarried couples is different from 8%.

3. A soft-drink manufacturer claims that its 12-ounce cans do not contain, on average, more than 30 calories. A random sample of 64 cans of this soft drink, which were checked for calories, contained a mean of 32 calories with a standard deviation of 8 calories. Does the sample information support the alternative hypothesis that the cans contain more than 30 calories? Use a significance level of 5%.

a) Based on your decision, which type of error could the sample data have led you to make? Explain what that means in the context of the question

4. A sample of 800 items produced on a new machine showed that 48 of them are defective. The factory will get rid the machine if the data indicates that the proportion of defective items is significantly more than 5%. At a significance level of 10% does the factory get rid of the machine or not?

5. The American Automobile Association (AAA) claims that 54% of fatal car/truck accidents are caused by driver error. A researcher studies 30 randomly selected accidents and finds that 14 were caused by driver error. At a significance level of , can the AAA claim be refuted?

6. A maker of frozen meals claims that the average caloric content of its meals is 800. A researcher tested an SRS of 12 meals and found that the average number of calories was 873 with a standard deviation of 100. Caloric content varies normally. Is there enough evidence to reject the claim at = 0.02?



b) Based on your decision, which type of error could the sample data have led you to make? Explain what that means in the context of the question.

Download 12.66 Kb.

Share with your friends:




The database is protected by copyright ©ininet.org 2024
send message

    Main page