NJGPA Statistics, Data Analysis, and Probability 2

Question 1

A spinner has 8 equal sections numbered 1 through 8. What is the probability of spinning an even number?

Accepted Answer

1/2

Answer

The even numbers are 2, 4, 6, and 8 — that's 4 out of 8 sections, giving a probability of 4/8 = 1/2.

Question 2

A frequency table shows that 12 students scored in the 80–89 range out of 40 total students. What percentage of students scored in this range?

Accepted Answer

30%

Answer

12 ÷ 40 = 0.30, and 0.30 × 100 = 30%, so 30% of students scored in the 80–89 range.

Question 3

Two events are independent if the outcome of one does not affect the outcome of the other. A fair coin is flipped twice. What is the probability of getting heads both times?

Accepted Answer

1/4

Answer

Each flip has a 1/2 probability of heads; since the flips are independent, multiply: 1/2 × 1/2 = 1/4.

Question 4

Which graphical display is best for showing how a single data set is distributed, including the median and quartiles?

Accepted Answer

Box plot

Answer

A box plot (box-and-whisker plot) directly displays the minimum, Q1, median, Q3, and maximum of a data set.

Question 5

A data set of test scores has a mean of 78 and a standard deviation of 5. Which score is closest to 2 standard deviations above the mean?

Accepted Answer

88

Answer

Two standard deviations above the mean: 78 + 2(5) = 78 + 10 = 88.

(NJGPA) New Jersey Graduation Proficiency Assessment Practice Test

(NJGPA) New Jersey Graduation Proficiency Assessment Practice Test

NJGPA Statistics, Data Analysis, and Probability 2