Read the situation. Then write the hypotheses in correct mathematical notation. Do not conduct any statistical tests. Just write the hypotheses. Insert your answers between the problems.

Here are some things to keep in mind:

1) On the Hypothesis Testing Worksheet, all you need to do is write the null and alternative hypotheses for each situation.

2) The null hypothesis will always be "=".

3) You can use either "≠" or "not =" for "does not equal". Greater than and less than is ">" or "<", respectively.

4) The alternative hypothesis wil be "not =" (2 tailed test) of ">" or "<" (one tailed test).

5) When determining what the null and alternative hypotheses are, realize that the alternative is the new information, what you are trying to prove. The null is what has been believed to be true up until now.

1) A bowler who has averaged 196 pins in the past year is asked to experiment with a ball made of a new kind of material. He rolls several games with the new ball. Has the new ball improved his game?

2) An advertisement claims that chewing NoCav gum reduces cavities. To test the claim, you conduct a study in which participants who chew the gum are compared to the national average of 3 cavities found per year.

3) In a speech to the Chamber of Commerce, a city councilman claims that in his city less than 15% of the adult male population are unemployed. An opponent in the upcoming election wants to test the councilman's claim.

4) The councilman is starting to get worried about the upcoming election. He has enjoyed 63% support for several years, but the political climate has been changing. He wants to know if his support has changed.

5) A production process is considered to be under control if the machine parts it makes have a mean length of 35.50 mm with a standard deviation of 0.45 mm. Whether or not the process is under control is decided each morning by a quality control engineer who bases his decision on a random sample of size 36. Should he ask for an adjustment of the machine on a day when he obtains a mean of 35.62 mm?

6) Jim, the owner of Jim's Grocery, knows that Plain Chips have always outsold Spicy chips. However, sales of Spicy chips have been increasing. Jim wants to determine if the average weekly sales of Spicy chips have indeed surpassed that of Plain chips.

7) Jim now wants to know if Plain and Spicy chips have the same percentage of defective product (i.e. underfilled bags, torn bags, wrong flavor in the bags, etc.).

8) The Great Vehicle Co. just introduced New SUV, claiming it can pull more weight than Old SUV. After testing 150 vehicles of each model, Old SUV had a mean pull weight of 5032 pounds with a standard deviation of 72 pounds. New SUV had a mean pull weight of 5462 pounds with a standard deviation of 154 pounds. Is the claim valid at a .05 level of significance?