Answer:
63.5
Step-by-step explanation:
1000× 6.35 / 100 = 63.5
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: 0.0930
Step-by-step explanation:
As per given , we have
H0: μcoffee = 6
Ha: μcoffee < 6
She finds z = −1.68 with one-sided P-value P = 0.0465.
The P-value for two-tailed test is calculated by :

For z= -1.68 , we have

![=2(1-P(z\leq1.68))\ \ [\because\ P(Z>z)=1-P(Z\leq z)]](https://tex.z-dn.net/?f=%3D2%281-P%28z%5Cleq1.68%29%29%5C%20%5C%20%5B%5Cbecause%5C%20P%28Z%3Ez%29%3D1-P%28Z%5Cleq%20z%29%5D)
Hence, the correct two-sided P-value for z = −1.68 is 0.0930 .