Question

The Nero Match Company sells matchboxes that are supposed to have an average of 40 matches per box, with σ = 8. A random sample of 90 matchboxes shows the average number of matches per box to be 42.6. Using a 1% level of significance, can you say that the average number of matches per box is more than 40?

a. What are we testing in this problem?

single mean

single proportion     

b. What is the level of significance?


c. State the null and alternate hypotheses.

H₀: μ ≥ 40; H₁:  μ < 40

H₀: μ = 40; H₁:  μ ≠ 40     

H₀: p = 40; H₁:  p ≠ 40

H₀: p ≤ 40; H₁:  p > 40

H₀: μ ≤ 40; H₁:  μ > 40

H₀: p ≥ 40; H₁:  p < 40

d. What sampling distribution will you use? What assumptions are you making?

The standard normal, since we assume that x has a normal distribution with known σ.

The standard normal, since we assume that x has a normal distribution with unknown σ.     

The Student's t, since we assume that x has a normal distribution with known σ.

The Student's t, since we assume that x has a normal distribution with unknown σ.

e. What is the value of the sample test statistic? (Round your answer to two decimal places.)


f. Estimate the P-value.

P-value > 0.250

0.125 < P-value < 0.250     

0.050 < P-value < 0.125

0.025 < P-value < 0.050

0.005 < P-value < 0.025

P-value < 0.005

g. Sketch the sampling distribution and show the area corresponding to the P-value.

h. Will you reject or fail to reject the null hypothesis? Are the data statistically significant at level α?

At the α = 0.01 level, we reject the null hypothesis and conclude the data are statistically significant.

At the α = 0.01 level, we reject the null hypothesis and conclude the data are not statistically significant.     

At the α = 0.01 level, we fail to reject the null hypothesis and conclude the data are statistically significant.

At the α = 0.01 level, we fail to reject the null hypothesis and conclude the data are not statistically significant.

i. Interpret your conclusion in the context of the application.

There is sufficient evidence at the 0.01 level to conclude that the average number of matches per box is now greater than 40.

There is insufficient evidence at the 0.01 level to conclude that the average number of matches per box is now greater than 40.

Answer 1