Answer: We will reject the null hypothesis.
Step-by-step explanation:
Since we have given that
Mean μ = 71.5 lbs
Standard deviation σ = 7.5 lbs
So, the hypothesis are given below:

Since α = 5% level of significance = 0.05
So, there is two tail test.
Critical values of z are 1.96 and -1.96.
So, we will reject H₀ if z<-1.96 or z>1.96
So, first we will find the value of z.

According to test statistic approach:
Since z >1.96
as 4.39>1.96
So, we will reject the null hypothesis.
Answer:
n = 98, that is, she scored at the 98th percentile.
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.
In this question, we have that:
She scored 38, so 
Test scores are normally distributed with a mean of 25 and a standard deviation of 6.4.
This means that 
Find the percentile:
We have to find the pvalue of Z. So



has a pvalue of 0.98(rounding to two decimal places).
So n = 98, that is, she scored at the 98th percentile.
<h2>
Answer:</h2>

<h2>
Step-by-step explanation:</h2>
If resistors are in series, so the current
is the same in all of them. In this problem we have four resistors. So, we can get a relationship between the Equivalent resistance of series combination and the four resistors as follows:

is the total resistance
. Moreover:

Therefore:

A) -4
d) -3.1
for these questions you have to subtract the two numbers since they have different signs and the biggest sign is the ending sign