Unit 1: Statistics Quiz

On a standardized test, Cathy had a score of 74, which was exactly 1 standard deviation above the mean. If the standard deviation for the test is 6, what is the mean score for the test?

• 68

• 71

• 77

• 80

On a standardized test, a score of 82 falls exactly 1 standard deviation below the mean.  If the standard deviation for the test is 4, what is the mean score for the test?

• 78

• 80

• 84

• 86

On a standardized examination, Laura received a score of 85, which was exactly 2 standard deviations above the mean.  If the standard deviation for the examination is 4, what is the mean for this examination?

• 93

• 87

• 83

• 77

Cheap and Fast gas station is conducting a consumer satisfaction survey. Which method of collecting data would most likely lead to a biased sample?

• interviewing every 5th customer to come into the station

• interviewing customers chosen at random by a computer at the checkout

• interviewing customers who call an 800 number posted on the customers' receipts

• interviewing every customer who comes into the station on a day of the week chosen at random out of a hat

A researcher randomly divides 50 bean plants into two groups He puts one group by a window to receive natural light and the second group under artificial light. He records the growth of the plants weekly. Which data collection method is described in this situation?

• observational study

• controlled experiment

• survey

• systematic sample

In a standard distribution, what is the greatest percent of the data that falls within 2 standard deviations of the mean?

• 95

• 81.5

• 68

• 34

On a standardized test with a normal distribution, the mean is 88. If the standard deviation is 4, the percentage of grades that would be expected to lie between 80 and 96 is closest to

• 5

• 34

• 68

• 95

Complete the equation: 
point estimate +/- _____

• standard deviation
• margin of error
• critical value
• confidence level

Increasing the sample size __________ the confidence interval. 

• increases
• decreases
• does not affect
• there is not enough evidence to determine the answer