Answer: 0.2643
Step-by-step explanation:
Let p be the population proportion and
be the sample proportion .
As per given question , we have

z-score : 

The required probability ( using z-table ):-

Hence, the probability that the proportion of books checked out in a sample of 478 books would be less than 13% = 0.2643
The best decimal equivalent is 10/16
It is likely D I am not positive
Answer:
We conclude that the mean nicotine content is less than 31.7 milligrams for this brand of cigarette.
Step-by-step explanation:
We are given the following in the question:
Population mean, μ = 31.7 milligrams
Sample mean,
= 28.5 milligrams
Sample size, n = 9
Alpha, α = 0.05
Sample standard deviation, s = 2.8 milligrams
First, we design the null and the alternate hypothesis

We use One-tailed t test to perform this hypothesis.
Formula:

Putting all the values, we have

Now,
Since,
We fail to accept the null hypothesis and accept the alternate hypothesis. We conclude that the mean nicotine content is less than 31.7 milligrams for this brand of cigarette.