Jesse takes two data points from the weight and feed cost data set to calculate a slope, or average rate of change. A ferret weighs 2.1 pounds and costs $3.40 per week to feed, while a Labrador Retriever weighs 70 pounds and costs $7.50 per week to feed. Using weight as the explanatory variable, $0.06 / lb.
is the slope of the line between these two points.
Solution
($7.50 - $3.40) / (70 lb. - 2.1 lb.) = $4.10 / 67.9 lb. $0.06 / lb.

Parents' income A confounder is a variable that influences both the dependent variable and independent variable, they can suggest there is correlation.

"For a sample of large n, the distribution of the count can be approximated with a normal distribution." - is NOT true about the distributions of counts and proportions.

The value of the z-test statistic would be -10. This can be calculated as follows:
Given data:
Sample mean (x ) = 2.9 inches
Population mean ( ) = 3 inches
Population standard deviation ( ) = 0.1 inch
Sample size (n) = 100
Calculate the z-test statistic:
z = (x - ) / ( / n)
z = (2.9 - 3) / (0.1 / 100)
z = (-0.1) / (0.1 / 10)
z = -1 / 0.01
z = -10
Therefore, the z-test statistic is -10.

A researcher has a table of data with four column variables and three row variables. The value for the degrees of freedom in order to calculate the chi squared statistic is 6.
df=(4 1)×(3 1)
df=3×2=6