The ages (in weeks) at which 6 infants learned to crawl are $23, 37, 33, 39, 29$, and $31$. What is the mean absolute deviation for the age at which the infants learned to crawl, to the nearest tenth?

The following data represent the age (in weeks) at which babies first crawl based on a survey of 12 mothers conducted by Essential Baby.

$$\begin{array}{cccccc}\hline 52 & {30} & {44} & {35} & {39} & {26} \\ \hline 47 & {37} & {56} & {26} & {39} & {28} \\ \hline\end{array}$$

(a) Draw a normal probability plot to determine if it is reasonable to conclude the data come from a population that is normally distributed. (b) Draw a boxplot to check for outliers. (c) Construct and interpret a 95% confidence interval for the mean age at which a baby first crawls.

Find the z-scores that separate the middle 88% of the data from the area in the tails of the standard normal distribution.

Find the equation of the regression line for the data. Then construct a scatter plot of the data and draw the regression line. (Each pair of variables has a significant correlation.) Then use 1he regression equation to predict the value of y for each of the x-values, if meaningful. If the x-value is not meaningful to predict the value of y, explain why not. If convenient, use technology. The ages (in years) of 10 infants and the numbers. of hours each slept in a day

$$\begin{matrix} \text{Age, x} & \text{0.1} & \text{0.2} & \text{0.4} & \text{0.7} & \text{0.6} & \text{0.9}\\ \text{Hours slept, y} & \text{14.5} & \text{14.3} & \text{14.1} & \text{13.9} & \text{13.9} & \text{13.7}\\ \text{Age, x} & \text{0.1} & \text{0.2} & \text{0.4} & \text{0.9} & \text{ } & \text{ }\\ \text{Hours slept, y} & \text{14.3} & \text{14.2} & \text{14.0} & \text{13.8} & \text{ } & \text{ }\\ \end{matrix}$$

(a) x = 0.3 year, (b) x = 3.9 years, (c) x = 0.6 year, (d) x = 0.8 year.

Find the equation of the regression line for the data. Then construct a scatter plot of the data and draw the regression line. (Each pair of variables has a significant correlation.) Then use 1he regression equation to predict the value of y for each of the x-values, if meaningful. If the x-value is not meaningful to predict the value of y, explain why not. If convenient, use technology. The number of goals scored and the number of wins for the top 10 teams in the 2016-2017 English Premier League season.

$$\begin{matrix} \text{Goals, x} & \text{85} & \text{86} & \text{80} & \text{78} & \text{77} & \text{54} & \text{62} & \text{41} & \text{55} & \text{43}\\ \text{Wins, y} & \text{30} & \text{26} & \text{23} & \text{22} & \text{23} & \text{18} & \text{17} & \text{12} & \text{12} & \text{12}\\ \end{matrix}$$

(a) x = 50 goals, (b) x = 70 goals, (c) x = 75 goals, (d) x = 95 goals.