12k-1 is the simplified answer
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.
Do you have any answer choices
Answer:
a. 
Step-by-step explanation:
<em>hey there,</em>
<em />
< There are 8 marks between 1 in. and 2 in. and here we can see that the distance of the line goes only up to the first mark.
Imagine this like a pizza that's divided into 8, but you only took 1 slice. That means you took only
of the pizza. It is the same here on the ruler.
It's not only 1/8 though because we also have to add in the first inch. After that inch, we also have 1/8 of an inch. So
in. would be your final answer. >
<u>Hope this helped! Feel free to ask anything else.</u>
By the way this problem is worded, he spends 75 minutes reading and cleaning, but there seems to be not enough information because the way it is worded, it means he has 75 minutes until he needs to GET READY, not play in the actual game. (40 + 35 = 75).