Question

Question A local pizza parlor advertises that 80% of its deliveries arrive within 30 minutes of being ordered. A local resident is skeptical of the claim and decides to investigate. From a random sample of 50 of the parlor’s deliveries, he finds that 14 take longer than 30 minutes to arrive. At the 10% level of significance, does the resident have evidence to conclude that the parlor’s claim is false? Identify the appropriate hypotheses, test statistic, p-value, and conclusion for this test. Select the correct answer below:

H0:p=0.80; Ha:p<0.80 z=−1.41; p-value=0.079 Reject H0. There is sufficient evidence to conclude that less than 80% of the pizza parlor’s deliveries arrive within 30 minutes of being ordered.

H0:p=0.80; Ha:p<0.80 z=1.26; p-value=0.104 Do not reject H0. There is insufficient evidence to conclude that less than 80% of the pizza parlor’s deliveries arrive within 30 minutes of being ordered.

H0:p=0.80; Ha:p<0.80 z=−1.41; p-value=0.159 Do not reject H0. There is insufficient evidence to conclude that less than 80% of the pizza parlor’s deliveries arrive within 30 minutes of being ordered.

H0:p=0.80; Ha:p<0.80 z=−1.41; p-value=0.079 Do not reject H0. There is insufficient evidence to conclude that less than 80% of the pizza parlor’s deliveries arrive within 30 minutes of being ordered.

Answer 1

The statistical software output for this problem is:

One sample proportion summary hypothesis test:
p : Proportion of successes
H₀ : p = 0.8
H_A : p < 0.8

Hypothesis test results:

Proportion	Count	Total	Sample Prop.	Std. Err.	Z-Stat	P-value
p	36	50	0.72	0.056568542	-1.4142136	0.0786

Hence,

H0:p=0.80; Ha:p<0.80 z=−1.41; p-value=0.079 Reject H0. There is sufficient evidence to conclude that less than 80% of the pizza parlor’s deliveries arrive within 30 minutes of being ordered.

Option A is correct.