Question

2) A publisher reports that 38% of their readers own a particular make of car. A marketing executive wants to test the claim that the percentage is actually different from the reported percentage. A random sample of 140 found that 28% of the readers owned a particular make of car. Find the value of the test statistic. Round your answer to two decimal places.

3) A sample of 900 computer chips revealed that 69% of the chips do not fail in the first 1000 hours of their use. The company's promotional literature states that 72% of the chips do not fail in the first 1000 hours of their use. The quality control manager wants to test the claim that the actual percentage that do not fail is different from the stated percentage. Determine the decision rule for rejecting the null hypothesis, H0, at the 0.02 level.

5) A manufacturer of chocolate chips would like to know whether its bag filling machine works correctly at the 438 gram setting. It is believed that the machine is underfilling the bags. A 28 bag sample had a mean of 433 grams with a standard deviation of 14. Assume the population is normally distributed. A level of significance of 0.1will be used. Find the P-value of the test statistic. You may write the P-value as a range using interval notation, or as a decimal value rounded to four decimal places.

Answer 1

Solution:

Question 2)

Given: A publisher reports that 38% of their readers own a particular make of car.

That is: p = 0.38

Claim: the percentage is actually different from the reported percentage.

Sample size = n = 140

Sample proportion of the readers owned a particular make of car =

We have to find the value of the test statistic.

Formula:

Thus the value of the test statistic is z = -2.44