Answer:

Step-by-step explanation:
The 90th percentile of a normally distributed curve occurs at 1.282 standard deviations. Similarly, the 10th percentile of a normally distributed curve occurs at -1.282 standard deviations.
To find the
percentile for the television weights, use the formula:
, where
is the average of the set,
is some constant relevant to the percentile you're finding, and
is one standard deviation.
As I mentioned previously, 90th percentile occurs at 1.282 standard deviations. The average of the set and one standard deviation is already given. Substitute
,
, and
:

Therefore, the 90th percentile weight is 5.1282 pounds.
Repeat the process for calculating the 10th percentile weight:

The difference between these two weights is
.
Answer:
The best estimate of the number of times out of 39 that Ariana is on time to class is 27.
Step-by-step explanation:
For each class, there are only two possible outcomes. Either Ariana is on time, or she is not. The probability of Ariana being on time for a class is independent of other classes. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
The expected value of the binomial distribution is:

The probability that Ariana is on time for a given class is 69 percent.
This means that 
If there are 39 classes during the semester, what is the best estimate of the number of times out of 39 that Ariana is on time to class
This is E(X) when n = 39. So

Rounding
The best estimate of the number of times out of 39 that Ariana is on time to class is 27.
Answer:
$2.16 per pound
Step-by-step explanation:
First, you would need to divide the price by the amount
$12.96 / 6 lbs = $2.16 per pound
That is the unit price
Answer:
c
Step-by-step explanation:
An angle is straight if and only if it’s measure is 180.