The answer is n=10 I already did this
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: Percent of people who had a mild allergic is 0.6%.
Step-by-step explanation:
Since we have given that
Total number of people try a new shampoo = 7000
Number of people had a mild allergic reaction = 42
We need to find the "Percentage of people had a mild allergic":
Percentage of people had a mild allergic is given by

Hence, Percent of people who had a mild allergic is 0.6%.
Answer:
Step-by-step explanation:
Mean: sum of terms/ number of terms
4 + 2 + 3 + 1 + 1 + 5 = 16
Numbr of terms = 6
16/6 = 2.66
Answered by g a u t h m a th
Answer:
σX = 3161
Step-by-step explanation:
The standard deviation is the square root of the multiplication of each probability multiplied by the squared difference between the values and the mean.
In this question:

Rounding to the nearest dollar, σX = 3161