Please I need help solving this questions:

1. The react times data set from our textbook has 50 observations of human reaction times to a physical stimulus. The reaction times are named Times and arranged in increasing order.

a. Find the mean and median of Times without using R. You may use your calculator.

b. Import react times into your workspace as a data frame with a single variable Times. Then calculate the mean of Times by using R's mean( ) function and the median with R's median( ) function.

c. Find the five number summary of Times and interpret each number.

d. Find the 60th percentile of Times without using R.

e. Find the 60th percentiles of Times using R.

f. Take off the 1st observation from reacttimes data, find the 60th percentiles of Times by using R.

2. The average public school teacher salaries in thousands of dollars for all 51 states and Washington D.C. are in the data set "teacher_salaries.txt".

a. Use R to make a boxplot of the variable Pay.

b. Describe the distribution of the variable Pay. Give, the shape, median, range, and any outliers.

c. Make a bar plot of the variable Region

3. Below is a stem-plot of the birth weights of male babies born to the smoking group. The stems are in units of kg.

The decimal point is at the | 1 | 9

2 | 346778889

3 | 223467899

4 | 12234

5 | 3556

6 | 1

a. Find the median birth weight.

b. Find the mean birth weight.

c. Find the sample standard deviation of the birth weight.

d. Which measurement would be best to use for measuring the center?

Justify your answer

4. The following information is from a sample of 15 women. They recorded the women's weight in pounds and height in inches. You can use R to answer all of these questions, no need to do by hand.

Height 58 58 59 61 61 63 64 65 67 67 67 70 72 72 72

Weight 117 117 120 123 123 139 142 142 146 146 150 150 150 154 164

a. Draw a scatterplot of the data. Describe the relationship between height and weight.

b. Determine the covariance and correlation coefficient (r) between height and weight. Give the interpretation of the correlation.

c. Suppose we want to predict the weight of a women based on the height. Give the least-squares equation to predict weight based on height.

d. If a women is 71 inches tall, what is the predicted weight?

e. Determine the coefficient of determination (R 2 ). Give the interpretation of this value.

f. If a women weights 148 lbs. and is 70 inches tall, what is the residual?