Question

Can we predict how fast a tennis player can hit a serve from the playerâs height? The following computer output and scatterplot describe the regression of fastest serve speed (in kilometers per hour) and the height (in meters) of 21 current male professional tennis players.
a. Describe the relationship between height and fastest serve speed for these tennis players.
b. Write the equation of the least-squares regression line. Define any variables used.
c. Interpret the value "R-sq = 27.7%".
d. What is the slope of the least-squares regression line? Interpret this value.
e. Predict the fastest serve of a professional tennis player whose is 1.7 meters tall. Comment on the reliability of this prediction.
f. What is the value of the correlation between height and fastest serve speed? Interpret this value.
g. Calculate the residual for the player that is 2.06 meters tall and has a fastest serve speed of 230 km/hr. Interpret this value.

Answer 1

Complete question :

The computer output and scatter plot output pertaining to the question can be found in the attached picture.

Answer:

Kindly check explanation

Step-by-step explanation:

A.) Relationship between height and fastest serve speed :

According to the scatterplot and Correlation Coefficient (R) value which can be obtauned by getting the square root of R²

R = √27.7%

R = 0.5263 = 52.63% ; this depicts a fairly strong positive correlation or relationship between height and fastest serve speed

B.)

Equation of least square regression line :

From the computer output and scatter plot above :

Recall :

y = mx + c

y =predicted variable (s fastest serve)

m= slope

x = predictor variable (height)

c = intercept

y = 84.98x + 68.81

C.) 27.7% of the variation in fastest speed can be explained by height while the remaining percentage is due to other variables

D.) fastest serve of tennis player with height 1.7m

y = 84.98x + 68.81

y = 84.98(1.7) + 68.81

y = 213.276km/hr

E.)

R = √27.7%

R = 0.5263 = 52.63% ; this depicts a fairly strong positive correlation or relationship between height and fastest serve speed

F.)

Height = 2.06m = x

y = 84.98(2.06) + 68.81

y = 243.8688 km/hr

Residual = Actual - predicted

Actual = 230 ; predicted = 243.8688

Residual = 230 - 243.8688

Residual = −13.8688

Hence, the model overestimated fastest serve speed of a 2.06 m tall player by −13.8688 km/hr