Do the data indicate a significant change in the grade distribution? Test at the .05 level of significance.

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### 6. Grade Distribution Analysis

A professor in the psychology department wants to determine if there has been a significant change in grading practices over the years. The historical grade distribution for the department in 1985 is as follows: 14% As, 26% Bs, 31% Cs, 19% Ds, and 10% Fs. A sample of 200 psychology students from last semester shows this distribution:

- A: 32
- B: 61
- C: 64
- D: 31
- F: 12

The question is: Do these data indicate a significant change in the grade distribution? Test at the 0.05 level of significance.

### 7. Automobile Insurance Cost Analysis

Automobile insurance is more expensive for teenage drivers than for older drivers. Insurance companies justify this by claiming that younger drivers are more likely to be involved in costly accidents. 

A researcher uses data from the department of motor vehicles and collects a sample of 300 accident reports from the police department. The registered driver's age distribution is as follows:

- 16% are under age 20
- 28% are aged 20 to 29
- 56% are aged 30 or older

The number of accident reports per age group is:

- Under Age 20: 68
- Age 20-29: 92
- Age 30 or Older: 140

**Question:** Do the data indicate that the number of accidents is related to the age group of the drivers?
Transcribed Image Text:### 6. Grade Distribution Analysis A professor in the psychology department wants to determine if there has been a significant change in grading practices over the years. The historical grade distribution for the department in 1985 is as follows: 14% As, 26% Bs, 31% Cs, 19% Ds, and 10% Fs. A sample of 200 psychology students from last semester shows this distribution: - A: 32 - B: 61 - C: 64 - D: 31 - F: 12 The question is: Do these data indicate a significant change in the grade distribution? Test at the 0.05 level of significance. ### 7. Automobile Insurance Cost Analysis Automobile insurance is more expensive for teenage drivers than for older drivers. Insurance companies justify this by claiming that younger drivers are more likely to be involved in costly accidents. A researcher uses data from the department of motor vehicles and collects a sample of 300 accident reports from the police department. The registered driver's age distribution is as follows: - 16% are under age 20 - 28% are aged 20 to 29 - 56% are aged 30 or older The number of accident reports per age group is: - Under Age 20: 68 - Age 20-29: 92 - Age 30 or Older: 140 **Question:** Do the data indicate that the number of accidents is related to the age group of the drivers?
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