Analytical Methods Midterm Exam
Q1. Your cell phone bill varies from month to month. Suppose your year has the following monthly amounts
46 33 39 37 46 30 48 32 49 35 30 48
Enter this data into a variable called bill. Use the sum command to find the amount you spent this year on the cell phone.
What is the smallest amount you spent in a month?
What is the largest?
How many months was the amount greater than $40? What percentage was this?
Q2. Find a graphic of bivariate data (any type) from the newspaper, Internet or other media source. Use R to generate a similar figure (please cite your source, be clear on your R code and the functions you are using)
Q3. The normal plot is a fancy way of checking if the distribution looks normal. A more primitive one is to check the rule of thumb that 68% of the data is 1 standard deviation from the mean, 95% within 2 standard deviations and 99.8% within 3 standard deviations.
Create 100 random numbers when the Xi are normal with mean 0 and standard deviation 1. What percent are within one standard deviation of the mean? Two standard deviations, three standard deviations? Is your data consistent with the normal? ((Hint: The data is supposed to have mean 0 and variance 1) (please use R commands and functions to respond)
Q4. An exit poll by a news station of 900 people in the state of Florida found 440 voting for Bush and 460 voting for Gore. Does the data support the hypothesis that Bush received p = 50% of the state's vote?