Statistics Review

What is a frequency?

• A percentage

• A histogram

• The number of times something happens

• The intervals on the x-axis

Manon's statistics professor puts a bonus question on every test, which adds 0.25 points to a student's overall grade at the end of the term. The above equation gives Manon's current overall grade, T, after taking into account q extra credit questions answered correctly. What does the 87 mean in this equation?

• Manon must get an 87 or above to pass.

• Manon's average is an 87 before adding the extra credit.

• After adding in her extra credit, Manon's average is an 87.

• Manon's professor gave 87 opportunities for extra credit this term.

A survey of a random sample of voters predicts that Candidate A will receive 41% of the votes, Candidate B will receive 40% of the votes, and Candidate C will receive 9% of the votes. The margin of error is ±5%. Which statement is correct about the percent of votes that the candidates might get?

• Candidate C will definitely get the highest percentage.

• Candidate A will get between 36% and 46% of votes.

• Candidate B will not get the highest percentage of votes.

• A clear winner can be predicted based on these results.

Suppose x is a normally distributed random variable with mean μ = 75 and standard deviation σ = 4. Find the probability that 71 < x < 81.

• 84%

• 53%

• 77%

• 7%

The heights of the students in a class are normally distributed with a mean of 64 inches and a standard deviation of 3 inches. What is the probability that a randomly selected student is less than 59.5 inches tall?

• 50%

• 9.3%

• 7%

• 14%

The class marks of a frequency distribution are given as : 15, 20, 25, ....
The class corresponding to the class mark 20 is _____

• 12.5 - 17.5

• 17.5 - 22.5

• 18.5 - 21.5

• 19.5 - 20.5

The class mark of the class 16 - 24 is ______

• 16

• 24

• 20

• None of the above

The difference between the maximum and minimum values of a variable is called ____

• Range 

• Variate

• Frequency

• None of the above

In a histogram the area of each rectangle is proportional to the class size of the corresponding class interval

• TRUE

• FALSE

How many more people have purple for a favorite color than red?

• 3

• 5

• 7

• 9