Question
A group of 100 students took a math exam, and the scores
were normally distributed with a mean of 75 and a standard deviation of 10. What is the percentage of students who scored between 60 and 90 on the exam?Solution
Since the scores are normally distributed, we can use the z-score formula to standardize the scores and find the percentage of students who scored between 60 and 90. First, we need to find the z-score for a score of 60 and a score of 90. The z-score formula is: z = (x - μ) / σ where x is the score, μ is the mean, and σ is the standard deviation. For x = 60, we have: z = (60 - 75) / 10 = -1.5 For x = 90, we have: z = (90 - 75) / 10 = 1.5 Now we can use a z-score table or a calculator to find the percentage of students who scored between -1.5 and 1.5 standard deviations from the mean. This percentage represents the percentage of students who scored between 60 and 90 on the exam. Using a z-score table, we find that the percentage of students who scored between -1.5 and 1.5 is approximately 86.6%. Therefore, about 86.6% of the students scored between 60 and 90 on the exam.
204, ?, 120, 83, 52, 23
What will come in place of (?) question mark in the given number series.
22, 23, 19, 28, ?, 37
31Â Â Â 40Â Â Â 51Â Â Â 64Â Â Â 79Â Â Â Â ?
137, 130, ?, 95, 67, 32
11, ? 220,  660, 1320,  1320Â
What will come in place of the question mark (?) in the following series?
2, 5, 8, 29, 112, ?
- What will come in place of the question mark (?) in the following series?
6, 19, 45, ?, 136, 201 22, 38, 74, 138, ?, 382
45, 58, 84, 123, ?, 240Â
2Â Â Â Â Â 3Â Â Â Â Â Â 5 Â Â Â Â Â Â 9Â Â Â Â Â Â ? Â Â Â Â Â Â 33
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