Please read assignment details

For each problem, you must calculate the deviations from the average, the manual correlation calculation and cross check it with Excel’s correl function. Furthermore, you will generate the scatterplot graph, along with the trendline. Indicate whether there is a strong/weak/no correlation between the two variables.

PRACTICE QUESTION 1:

The Swiss Hiking Federation is an organization that is known for promoting the same use of the hiking trail system throughout Switzerland. Suppose SHF would like to investigate the linear relationship between the amount of time to hike Wengen-Kleine trail in the Jungfrau region and the age of the hiker. A random sample of 7 hikers on this trail was selected and their age and hiking time is below.

AGE: 24 32 47 40 26 53 38

TIME: 2.7 4.2 5.0 3.8 2.2 2.9 3.0

Using XLS, calculate the correlation coefficient for this sample. Test to see if the population correlation coefficient is not equal to zero using a 90% CI. Here, you will use a two-tail test.

PRACTICE QUESTION 2:

Consider the following

X: 4 7 2 6 6

Y: 6 9 5 5 7

Using XLS, calculate the correlation coefficient for this sample. Test to see if the population correlation coefficient is not equal to zero using significance of 0.05. What are your conclusions?

PRACTICE QUESTION 3:

Fair Isaac, the company that developed the credit score (FICO) model used by most lenders today, would like to test the linear relationship between age and credit score of an individual. The follow table shows the credit scores and ages of 10 randomly selected individuals:

AGE: 36 24 54 28 31 47 35 59 40 42

FICO: 675 655 760 615 660 790 720 760 685 610

Using XLS, calculate the correlation coefficient for this sample. Test to see if the population correlation coefficient is different from zero, using an significance of 0.02. What are your conclusions?

PRACTICE QUESTION 4:

The following tables shows the selling prices, in thousands of dollars, and the square footages of seven randomly selected homes recently sold by Century 21 Realtors:

Price: 258 191 253 168 249 245 282

Sqr Ft: 2730 1860 2140 2180 2310 2450 2920

Using XLS, calculate the correlation coefficient for this sample. Using an significance of .1, test the significance of the population correlation coefficient between a house’s selling price and its square footage. What conclusions can you draw?

PRACTICE QUESTION 5:

The following tables shows the mpg and curbed weight, in thousands for eight randomly selected vehicles:

MPG: 28 22 20 34 41 15 19 15

Weight: 2730 2860 3140 2180 2310 4450 3920 2590

Using XLS, calculate the correlation coefficient for this sample. Using an significance of .1, test the significance of the population correlation coefficient is negatively related between mpg and curbed weight. What conclusions can you draw?

USE EXCEL TO ANSWER THE FOLLOWING:

A container of one dozen large eggs was purchased at a local grocery store. Each egg was measured to determine its diameter (in millimeters) and weight (in grams). The results for the 12 eggs are given in the following table. Weight is the dependent variable. Calculate the r-sqr, correlation coefficient, and explain each value.

Index | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |

Diameter (mm) | 42.2 | 45.45 | 47.8 | 47.4 | 47.7 | 43.5 | 44.4 | 43.9 | 46.2 | 45.9 | 44.3 | 44.5 |

Weight (grams) | 52.8 | 58.5 | 60.2 | 59 | 57.4 | 54.1 | 53.9 | 54.5 | 56.2 | 55.8 | 54.3 | 56.1 |

The following table gives information on the amount of sugar (in grams) and the calorie count in one serving of a sample of 13 varieties of Kellogg’s cereal. Calories is the dependent variable. Calculate the r-sqr, correlation coefficient, and explain each value.

Index | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 |

Sugar (grams) | 4 | 15 | 12 | 11 | 8 | 6 | 7 | 2 | 7 | 14 | 20 | 3 | 13 |

Calories | 120 | 200 | 140 | 110 | 120 | 80 | 190 | 100 | 120 | 190 | 190 | 110 | 120 |