FREE CLAST Statistics and Probability Questions and Answers

Question 1

A college president is curious about the most well-liked courses among students. The president makes the decision to poll a representative sample of students. Which method would be best for gathering a representative sample of college students from a statistically neutral perspective?

Accepted Answer

Survey a random sample of students from a list of the entire student body

Answer

To obtain a statistically neutral and representative sample, every member of the population must have an equal chance of being selected. Surveying a random sample from a complete list of the entire student body ensures this randomness and avoids biases. Other methods, like surveying specific departments or using voluntary responses, would introduce sampling bias.

Question 2

The average number of school-age children per home in a city must be determined by the primary school board. The board decides to run a poll in order to achieve this. What process would be most suitable for choosing a statistically unbiased sample?

Accepted Answer

Randomly select geographic regions of the city and then survey a random sample of people within the regions

Answer

Randomly selecting geographic regions and then surveying a random sample within those regions is an effective method for large, geographically dispersed populations, known as cluster sampling. This approach helps ensure a diverse and representative sample of households across the city. Other options would introduce bias by focusing on specific locations or groups not representative of the entire city's households.

Question 3

What mode can you identify in the example below?
11, 29, 21, 2, 28, 29, 18, 29, 6, 29, 29

Accepted Answer

29

Answer

The mode of a data set is the value that appears most frequently. In the given set (11, 29, 21, 2, 28, 29, 18, 29, 6, 29, 29), the number 29 appears 5 times. Since no other number appears as often, 29 is the mode.

Question 4

What does the following sample mean look like?
6, 4, 28, 21, 28, 28, 26, 28, 14, 9, 28

Accepted Answer

20

Answer

The mean (average) is calculated by summing all the values in the data set and then dividing by the total number of values. For the given data (6, 4, 28, 21, 28, 28, 26, 28, 14, 9, 28), the sum is 220. Since there are 11 values, the mean is 220 divided by 11, which equals 20.

Question 5

For ten days, the number of patients Dr. Smith's dental practice saw each day was noted. Find the sample's mean, median, and mode using the provided data.
3, 26, 8, 22, 30, 30, 6, 15, 21, 28

Accepted Answer

18.9, 21.5, 30

Answer

First, order the data: 3, 6, 8, 15, 21, 22, 26, 28, 30, 30. The mean is the sum (189) divided by the count (10), which is 18.9. The median, for an even number of data points, is the average of the two middle values (21 and 22), so (21+22)/2 = 21.5. The mode is the value that appears most frequently, which is 30.

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CLAST Practice Test Practice Test

FREE CLAST Statistics and Probability Questions and Answers