1. What’s the answer? To this problem??
2 answers:
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Answer:
See Image below:)
Step-by-step explanation:
You can use the app photo math, you just take a picture of the question and it shows you the steps.
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:
Step-by-step explanation:
Hello!
You have two populations of interest and want to compare them. If you define the study variables as:
X₁: average hourly wages of an employee of the Downtown store.
n₁= 25
X[bar]₁= $9
S₁= $2
X₂: average hourly wages of an employee of the North Mall store.
n₂= 20
X[bar]₂= $8
S₂= $1
Both samples taken are independent, assuming that both populations are normal and that their population variances are equal I'll use the Student's-t statistic with a pooled sample variance to calculate the Confidence interval:
95% CI for μ₁ - μ₂
(X[bar]₁-X[bar]₂) ±
Sa= 1.64
(9-8)±2.017*
[0.007636;1.9923]
I hope it helps!