Question

Examine the two-way frequency table below.

Score: 90-100 Score: 70-89 Score: 0-69
Math Test 20 40 7
Science Test 15 35 5
Which percentage of students took the math test and received a grade of 90 or above?


16.39%

29.85%

57.14%

28.69%
Let event A = "math test" and event B = "Score: 90-100." Then find , where

Answer 1

To find the percentage of students who took the math test and received a grade of 90 or above, we need to calculate the conditional probability P(A ∩ B), which is the probability of event A ("math test") and event B ("Score: 90-100") happening simultaneously.

From the two-way frequency table:

The number of students who took the math test and received a grade of 90 or above is 20.

The total number of students who took the math test is 20 + 40 + 7 = 67.

Now, we can calculate the conditional probability:

P(A ∩ B) = (Number of students who took the math test and received a grade of 90 or above) / (Total number of students who took the math test) × 100%

P(A ∩ B) = 20 / 67 × 100% ≈ 29.85%

So, the percentage of students who took the math test and received a grade of 90 or above is approximately 29.85%.