Question

Amanda earned a score of 940 on a national achievement test that was normally distributed. The mean test score was 850 with a standard deviation of 100. What proportion of students had a higher score than Amanda? Use your z table.

Question 6 options:

0.82


0.10


0.18


0.32

Answer 1

ageta

Answer 2

@ageta

Answer 3

tnxs

Answer 4

To solve this question, you'll need to use a table of the standardized Normal distribution. Fortunately, you can just use a graphing calculator, or you can find a Normal distribution calculator on the internet. It'll ask for the three facts from your question. (If the calculator also asks for cumulative

Answer 5

comulative probability

Answer 6

Standard score 940
Mean 850
Standard deviation 100

Answer 7

So, the answer will be the cumulative probability, which will be a number with a few decimals. However, this represents the students who had a LOWER score than Vivian. You'll need to subtract this from 1 in order to get the opposite number, the proportion of students who had a higher score than Vivian. Be sure to multiply the result by 100 to get a percentage. That's it.

Answer 8

σ = (940 - 850) / 100 = 0.90.

Answer 9

he's wrong

Answer 10

In math notation, we've done this: z = (X - μ) / σ = (940 - 850) / 100 = 0.90
where z is the z-score
X is Vivian's score (940)
µ is the mean (850)
σ is the standard deviation (100)

As you may know, in a normal distribution it's expected that about 68% of all observations will fall within 1 standard deviation of the mean, 95% will fall within 2 standard deviations, and 99% will fall within 3 standard deviations. You now have all the info you need to do a rough calculation of the cumulative probability. Here's how to put it together:

The upper half of the 68% (the scores between the mean and the first standard deviation) = 34%
Vivian's 90% of the 34% = 30.6%

All the test scores lower than the mean = 0.500 (this is 1/2 of all test scores)
+ All the test scores between the mean and Vivian's score = 0.306 (see above)

= 0.806, which is not the real cumulative probability, but an approximation

Answer 11

0.086

Answer 12

:3

Answer 13

wait what

Answer 14

so which one is it?

Answer 15

yeah boldjon is right 0.086

Answer 16

so its a

Answer 17

yeah i guess

Answer 18

ok preciate it