91影视

Information obtained for the month that is $6$months after the birth month:

Scatterplot for average temperature and average crawling age relationship:

On horizontal axis,

Average temperature has been represented.

On vertical axis,

Average crawling age has been represented.

Form: Linear, because in the scatterplot no strong curvature exists.

Strength: Moderately strong, because the points in the scatterplot are not spread far apart and do not lie extremely close together.

Unusual features: It has been shown that the leftmost in the scatterplot seems to deviate from the general linear pattern in the other points; one outlier appears to be there.

Direction: Negative, the pattern slops downward in the scatterplot.

This implies

There is a negative, linear, moderately strong association between the average temperature and the average crawling age, an outlier also exists in the scatterplot.

Least 鈥� squares regression line (general equation):

$\hat{y}=b_0+b_{1}x$

From computer output,

Slope $b_1$estimate has been provided in row 鈥淎verage temperature鈥� and column 鈥淐oef鈥�:

$b_1=-0.0777$

And

Constant $b_0$estimate has been provided in row 鈥淐onstant鈥� and column 鈥淐oef鈥�:

$b_0=35.68$

Substitute the values of $b_1$and $b_0$in the general equation of the least 鈥� square regression line:

role="math" localid="1663583182993" $\hat{y}=b_0+b_{1}x=35.68-0.0777x$

Where,

x: average temperature

y: average crawling age

From Part (b),

Least 鈥� squares regression line general equation:

$\hat{y}=b_0+b_{1}x=35.68-0.0777x$

Where,

x: average temperature

y: average crawling age

Now,

In the least square regression equation,

The slope is the coefficient of $x$.

And

Also represents the average increase (or decrease) of $y$ per unit of $x$.

Thus,

On average, the average crawling age drops by an average temperature of$0.0777$weeks per$掳F$.

From Part (a),

We came to know that

There was a linear, negative, moderately strong association between the average temperature and average crawling age.

However,

This association does not mean causation.

Which means

The increasing average temperature does not necessarily cause a decrease in average crawling age.

Thus,

We cannot conclude that warmer temperature $6$months after babies are born causes them to crawl sooner.