Statistical HW

HW 4

1. The following data were gathered on voting preference. Use a χ2 to determine if there is a gender gap in voting preference. Show all the steps.

2. Perform a Mann Whitney U on the following data and answer the question of whether either brand lasts longer than the other.

3. Laureysens et al. (2004) measured metal content in the wood of 13 poplar clones growing in a polluted area, once in August and once in November. Concentrations of aluminum (in micrograms of Al per gram of wood) are shown below. Are the samples different, use a Wilcoxon rank test?

4. 27 people were asked to sample and rate 3 wines. Their ratings are below. Use a Kruskall Wallace test to determine if there is any difference in the three cheeses.

New Old Control

5. 12 people were asked to sample and rate 3 cheeses. Their ratings are below. Use a Friedman test to determine if there is any difference in the three cheeses.

6. You collect the following data examining how a cars gas mileage relates to its horsepower. Use a Spearman correlation to examine the relationship.

7. Is there a difference in the number of students in statistics courses through the years? Use a Chi-Squared test. Show all the steps.

BrandLife in Months

X2

X2

X3

X4

X6

Y4

Y6

Y7

Y8

Y10