### Posts tagged with confidence intervals

## Hypothesis Testing Assignments

- The Florida Department of Labor and Employment Security reported the state mean annual wage was $26,133. A hypothesis test of wages by county can be conducted to see whether the mean annual wage for a particular county differs from the state mean.

a. Formulate the hypothesis that can be used to determine whether the mean annual wage in Baker county differs from the state annual mean wage of $26,133.

b. A sample of 550 people in Baker County showed a sample mean of $25,457. Assume a population standard deviation of $7600. What is the p-value? Use a significance level of 5%. What is your conclusion? - Glow toothpaste maintains that their tubes have always contained an mean of 12 ounces. The production group believes that the mean weight has changed. The weight in ounces for a sample of 15 tubes of toothpaste had an average value of 12,09 ounces and a standard deviation of 0.20 ounces. Use an appropriate hypothesis test to determine if the data show evidence of change in the mean weight. Use 90% confidence level.
- Enumerate the 36 possible outcomes from rolling a pair of dice, and compute the probability of rolling each of the numbers from 2 to 12.
- The Excel file contains mean temperatures for January and July and average annual precipitation for selected cities across the U.S. Construct 90% confidence intervals for the mean temperatures and precipitation.
- If, based on a sample size of 100, a political candidate found that 59 people would vote for her in a two-person race. What is the 95% confidence interval for her expected proportion of the vote?
- The Excel file contains the list of all the 76 items McDonalds serve and they are classified as sandwiches, fries, chicken pieces, salads, breakfasts, and desserts/shakes. Each record contains the serving size, calories, fat, cholesterol, sodium, and carb contents. For the entire month of September 1-30, you ate one of the sandwiches picked randomly from the list for dinner. Now you are sick of eating sandwiches. You decided to eat a salad for the entire month of October 1-31, picked in the same way you did in September. Your task is to analyze the data, summarize your experience and compare the differences between September and October. You have in your possession some very powerful statistical tools:

a. Descriptive Statistics;

b. Sampling;

c. Confidence Interval;

d. Hypothesis Testing:

e. Graphical display.