Answer:
The value that represents the 90th percentile of scores is 678.
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:

Find the value that represents the 90th percentile of scores.
This is the value of X when Z has a pvalue of 0.9. So X when Z = 1.28.




The value that represents the 90th percentile of scores is 678.
Answer:
64 books
Step-by-step explanation:
The first step is to find the number of books that will fit in the shelve per foot
= 40/5
= 8
Therefore the number of books that will fit perfectly in 8-foot shelf can be calculated as follows
= 8×8
= 64
Hence 64 books would fit in 8-foot shelf
Answer:
he will have to pay $650 in the month of june
Answer:
The complement event would be: "No rain today"
Its probability would be 70%
Step-by-step explanation:
Given the event:
A= rain today
The probability of rain today is 30%
P(A)=30%=0.3
The complement event has all the values that are not included in the event.
The complement event would be:
A'= No rain today
The probability of a event is the subtraction between 1 and the complement event:
P(A')=1-P(A)
Then, the probability of the event "No rain today" will be:
P(A')=1-0.3=0.7=70%
Answer:
the value is....
Step-by-step explanation:
a