When testing gas pumps for accuracy, fuel-quality enforcement specialists tested

Question

When testing gas pumps for accuracy, fuel-quality enforcement specialists tested pumps and found that 1294 of them were not pumping accurately (within 3.3 oz when 5 gal is pumped), and 5661 pumps were accurate. Use a 0.01 significance level to test the claim of an industry representative that less than 20% of the pumps are inaccurate. Use the P-value method and use the normal distribution as an approximation to the binomial distribution. Identify the null hypothesis and alternative hypothesis. A. H_0 middot p = 0.2 H_1 middot p notequalto 0.2 B. H_0 middot p = 0.2 H_1 middot p > 0.2 C. H_0 middot p = 0.2 H_1 middot p

Explanation / Answer

The hypotheses:

H0:p=0.2

H1:p<0.2

Ans: Option C)

The test statistic is:

Z=(Ps-Pu)/sqrt [Pu(1-Pu)/N], where, Ps is sample proportion and Pu is population proportion, N is the sample size.

Ps=1294/6995=0.18

Z=(0.18-0.2)/sqrt [0.2(1-0.2)/6995]=-4.18

The p value corresponding to Z=-4.18 is 0.0000. This is less than 0.01. Therefore, reject null hypothesis to conclude that less than 20% of pumps are inaccurate.

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.