1. Prompted by a curiosity over whether the current NFC South is the worst division in the history of the NFL, a sportswriter examines the distribution of Super Bowl wins by division. This is the number of Super Bowl wins by current NFL division:

Division	Super Bowl Wins
NFC East	13
AFC East	9
AFC West	8
AFC North	8
NFC West	8
NFC North	5
NFC South	3
AFC South	2

Using this data ( ), determine if the distribution of Super Bowl wins across divisions is significantly different from uniform. In addition to your ultimate decision, include the chi-square statistic, degrees of freedom, and chi-square critical value.

2. Opticians are curious whether the type of vision correction that customers use is associated with how often they find themselves thinking about their vision. They ask four groups of vision correction consumers (eye glasses wearers, contact wearers, Lasik recipients, and people with no vision correction) about whether they think about their vision frequently, sometimes, or never. Using the data below, determine if there is a significant difference in vision consideration by type of vision correction ( ). In addition to your ultimate decision, include the chi-square statistic, degrees of freedom, and chi-square critical value.

Vision Correction	Frequently	Sometimes	Never	Total
Glasses	45	40	15	100
Contacts	35	50	15	100
Lasik	15	40	45	100
No Correction	5	20	75	100
Total	100	150	150	400

3. Consumer scientists are curious if there is a difference in level of complaints that employees receive by commercial sector. Observing 100 consumer-employee interactions, they document whether the consumer complained and the sector. Using the data below, determine if there is a significant difference in complaints by commercial sector ( ). In addition to your ultimate decision, include the chi-square statistic, degrees of freedom, and chi-square critical value.

Sector	Complained	Did not Complain	Total
Food	15	10	25
Retail	10	10	20
Pharmacy	10	20	30
Tech Support	15	10	25
Total	50	50	100