Proctor & Gamble claims that at least half the bars of Ivory soap they produce a

Question

Proctor & Gamble claims that at least half the bars of Ivory soap they produce are 99.44% pure (or more pure) as advertised. Unilever, one of Proctor & Gamble's competitors, wishes to put this claim to the test. They sample the purity of 131 bars of Ivory soap. They find that 57 of them meet the 99.44% purity advertised.

What type of test should be run?

A) z-test of a proportion

B) t-test of a mean

The alternative hypothesis indicates a

A) right-tailed test

B) left-tailed test

C) two-tailed test

Calculate the p-value. __________

Does Unilever have sufficient evidence to reject Proctor & Gamble's claim?

A) Yes

B) No

Explanation / Answer

Below are the null and alternate hypothesis
H0: p = 0.5
H1: p < 0.5

This is left tailed test

n = 131
pcap = 57/131 = 0.4351

This is z-test of proportion

SE = sqrt(0.5*0.5/131) = 0.0437

Test statistics, z = (0.4351 - 0.5)/0.0437 = -1.485

p-value = 0.0688

Fail to reject null hypothesis at significance level of 0.05
Unilever does not have sufficient evidence to reject P&G's claim.

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

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