PSSA Data Analysis and Statistics Flashcards

A bag contains 4 red marbles, 3 blue marbles, and 5 green marbles. If one marble is drawn at random, what is the probability it is NOT green?

Answer: 7/12

There are 4 + 3 = 7 non-green marbles out of 12 total, so P(not green) = 7/12.

The following data represents students' quiz scores: 70, 75, 80, 80, 85, 90, 95. What is the range?

Answer: 25

The range is the difference between the maximum and minimum values: 95 - 70 = 25.

A pie chart shows that 25% of students chose math as their favorite subject. If 200 students were surveyed, how many chose math?

Answer: 50

25% of 200 = 0.25 × 200 = 50 students chose math as their favorite subject.

Which measure of central tendency is MOST affected by an outlier (an extremely high or low value)?

Answer: Mean

The mean is most affected by outliers because it includes all values in its calculation, pulling the average toward extreme values.

A double bar graph compares boys' and girls' favorite sports. If 15 boys and 10 girls prefer swimming, what fraction of the total (25) prefer swimming?

Answer: 3/5

15 boys + 10 girls = 25 prefer swimming; 25/25 students in the swimming category means 3/5 of the boys prefer swimming (15/25 = 3/5).

A frequency table shows: 1-10: 5 students, 11-20: 8 students, 21-30: 12 students, 31-40: 3 students. Which interval has the highest frequency?

Answer: 21–30

The interval 21–30 has 12 students, which is the highest frequency among all four intervals.

If you flip a fair coin twice, what is the probability of getting heads both times?

Answer: 1/4

Each flip has a 1/2 probability of heads; for two independent events: 1/2 × 1/2 = 1/4.