Statistics : For the following data (A) calculate the correlation coefficient
Statistics : For the following data (A) calculate the correlation coefficient
Subject: Mathematics / Statistics
Question
1. For the following data (A) calculate the correlation coefficient r, and (B) make a conclusion about
the type of correlation.
The ages (in years) of 66 children and the number of words in their vocabulary
Age, x
1 2 3
4
5
6
Vocabulary size, y 150 650 1000 1700
2000 2700
(A) The correlation coefficient r =
(B) What is the conclusion about the correlation
2. For the following data (A) calculate the sample correlation coefficient r, and (B) make a
conclusion about the type of correlation.
The earnings per share (in dollars) and the dividends per share (in dollars) for 66 medical supplies
companies in a recent year are shown in the data set below.
Earnings per share, x 2.74 5.06 4.52 3.04 3.73 2.21
Dividends per share, y 0.58 2.38 1.41 0.85 1.07 0.29
(A) The correlation coefficient r =
(B) What is the conclusion about the correlation
3.The weights (in pounds) of 6 vehicles and the variability of their braking distances (in feet)
when stopping on a dry surface are shown in the table. Can you conclude that there is a
significant linear correlation between vehicle weight and variability in braking distance on a
drysurface? Use a=0.01
Weight, x
5980
Variability in braking distance,
1.71
y (A) H0: p =
(B) Ha: p =
(C) Identify the critical value(s)
(D) Calculate the test statistic = 5350 6500 5100 5880 4800 1.95 1.91 1.57 1.65 1.50