91Ó°ÊÓ

The null hypothesis of a statistical hypothesis test always predicts that there is no impact or association between variables.

From the given information it is said that,

$x=63$

$n=273$

When finding the null hypothesis i.e

$$\begin{gathered} p=\frac{x}{n} \\ p=\frac{63}{273} \\ p=23 \end{gathered}$$

We can see that value of $p$is less than $30\%$, Therefore, it is not the correct option.

From the given information it is said that,

$x=63$is the number of teen girls who smoke to stay thin.

$n=273$is the group of teen girls randomly selected.

When finding the null hypothesis i.e

$$\begin{gathered} p=\frac{x}{n} \\ p=\frac{63}{273} \\ p=23 \end{gathered}$$

Therefore,

$p≤0.30$cannot be the correct answer as the number of girls smoking to stay thin is less than$30\%$and here it is less than and equal to$30\%$

From the given information it is said that,

$x=63$is the number of teen girls who smoke to stay thin.

$n=273$is the group of teen girls randomly selected.

When finding the null hypothesis i.e

$$\begin{gathered} p=\frac{x}{n} \\ p=\frac{63}{273} \\ p=23 \end{gathered}$$

Therefore,

As the null hypothesis states that either $30$or less than $30\%$of girls smoke to stay thin, hence, the alternate hypothesis has to say that greater than $30\%$of girls smoke to stay thin. The alternate hypothesis always opposes the null hypothesis.

To calculate we are given,

$x=63$is the number of teen girls who smoke to stay thin.

$n=273$is the group of teen girls randomly selected.

$$\begin{gathered} p=\frac{x}{n} \\ p=\frac{63}{273} \\ p=23 \end{gathered}$$

$23\%$of the girls actually smoked to stay thin. The number of girls smoking to stay thin is less than $30\%.$