Chapter 5.1, Problem 22E

(a)

To determine

To Explain: the reason of sample outcomes 27 out of 60 said “Yes” does not allow convincing proof that fewer than half of the school’s brush their teeth with the water off.

Answer to Problem 22E

There is having many dots above the 0.45 in the dot plot.

Explanation of Solution

Given:

  

18 outcomes from 60 students said “Yes”

  $\frac{27}{60}=\frac{9}{20}=0.45$

By seeing the dot plot, it is notice that the proportion of 0.45 has many dots above it. Therefore it is too much likely to get a proportion of 0.45 if the true proportion is 0.5 and then there is not enough proof to help the claim that fewer than half of the school’s students brush their teeth with the water off, the reason is that the sample result are likely to occur.

(b)

To determine

To Explain: the reason of result would offer convincing proof that fewer than 50% of the school’s students brush their teeth with the water off.

Answer to Problem 22E

There is having no dots above 0.30 and also not it’s left in the dot plot.

Explanation of Solution

Given:

  

18 outcomes from 60 students said “Yes”

  $\frac{18}{60}=\frac{3}{10}=0.3$

By seeing the dot plot, it is observed that the above 0.30 there is no dots and also no dots to the left of the 0.30. Therefore is too much likely to get a proportion of 0.30 if the true proportion is 0.3 and then there is enough proof to help the claim that fewer than 50% of the school’s students brush their teeth with the water off, the reason is that the sample result are too much not likely to get.