Answer:
The top 20% of the students will score at least 2.1 points above the mean.
Step-by-step explanation:
When the distribution is normal, we use the z-score formula.
In a set with mean and standard deviation , the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
The mean of a certain test is 14 and the standard deviation is 2.5.
This means that
The top 20% of the students will score how many points above the mean
Their score is the 100 - 20 = 80th percentile, which is X when Z has a pvalue of 0.8. So X when Z = 0.84.
Their score is:
16.1 - 14 = 2.1
The top 20% of the students will score at least 2.1 points above the mean.
Answer:
What Did the Blind Man Say after Being Handed a Cheese Grater?
"That's the most violent book I've ever read."
Step-by-step explanation:
Answer:
B. x= 3y+2
Step-by-step explanation:
y=⅓x-⅔
⅔+y=⅓x
(⅔÷⅓)+(y÷⅓)=⅓x÷⅓
2+3y=x
Answer:
5(37)+10
10(17.5)+5
Step-by-step explanation:
5x+10=180
-10 -10
5x=170
divide by 5
x=37
---------------------
10x+5=180
-5 -5
10x=175
divide by 10
x=17.5
Answer:
Step-by-step explanation:
Using the rule of exponents
⇔
Evaluating from the inside parenthesis outwards
= - × - = , then
= = 9² = 81 , then
=