Answer:
The reading speed of a sixth-grader whose reading speed is at the 90th percentile is 155.72 words per minute.
Step-by-step explanation:
Problems of normally distributed samples are solved using 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.
In this problem, we have that:

What is the reading speed of a sixth-grader whose reading speed is at the 90th percentile
This is the value of X when Z has a pvalue of 0.9. So it is X when Z = 1.28.




The reading speed of a sixth-grader whose reading speed is at the 90th percentile is 155.72 words per minute.
Answer:
A
ellipse
Step-by-step explanation:
Answer:
G=7
Step-by-step explanation:
4(g-1)=24
4g-4=24
4g=28
g=7
Answer:
It takes 1 minute 12 seconds to fill the bucket if both taps are turned on.
Step-by-step explanation:
- One tap fills the bucket in 2 minutes, thus fills 1/2 of the bucket in one minute.
- Other tap fills the bucket in 3 minutes, thus fills 1/3 of the bucket in one minute.
- Both together fill 1/2+1/3=5/6 of the bucket in one minute.
- If they can fill 5/6 of the bucket in 1 minute, they fill 1/6 of the bucket in 1/5 minute.
- They can fill the bucket (6/6) in 1+1/5 minute
- This is 1 minute 12 seconds