A report claims that 30% of adults own more than one car, but an automobile manufacturer has reason to believe the true percentage is higher than 30%.  Upon surveying a random sample of adults, the automobile manufacturer finds that 33% of the adults in the sample own more than one car.  The hypothesis test correctly yields z = 2.0.  Based on this information, what should be concluded?  单项选择题

A

If a two-sided alternative hypothesis had been set up, the null hypothesis would not have been rejected at 𝛼 = 0.05.

B

Because the resulting P-value is smaller than 0.05, this means there is less than a 5% chance the original claim is true.

C

The value of z = 2 shows the data are close enough to the original claim that we should keep assuming that claim is true.

D

Since the P-value is smaller than 0.05, this proves that more than 30% of all adults own more than one car.

E

The standard deviation of the sampling distribution must be smaller than 0.03.

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