Answer:
The 90% confidence interval for population mean is 
Step-by-step explanation:
From the question we are told that
The sample mean is 
The confidence level is 
The sample size is 
The standard deviation
Now given that the confidence level is 0.90 the level of significance is mathematically evaluated as


Next we obtain the critical value of
from the standardized normal distribution table. The values is 
The reason we are obtaining critical values for
instead of that of
is because
represents the area under the normal curve where the confidence level 1 -
(90%) did not cover which include both the left and right tail while
is just considering the area of one tail which is what we required calculate the margin of error
Generally the margin of error is mathematically evaluated as

substituting values


The 90% confidence level interval is mathematically represented as

substituting values



95/294 orrr 0.3231 And you just round that to the nearest 10th
Answer: Plan B
Step-by-step explanation:
First you would find out how much they have to pay the monthly fee in 5 months. Plan A pays $50 in 5 months and Plan B pays $30 in 5 months
Then you find he amount of money that they need to pay for a hundred texts. Plan A spends $25 and Plan B spends $35 .
Then you add the numbers together and Plan A you would pay $75 and Plan B you would spend $65
Answer:
4a. About 54 times NOT INCLUDING THE FIRST TRIAL
4b. About 60 times NOT INCLUDING THE FIRST TRIAL
Step-by-step explanation:
I say about because we don't know if it's ALWAYS going to be the same results.
4a. Also 12*4 because it's 20 times so 20*4=80 then you add half of it to become 90 and you get 54
4b. 12*5 because 100/5=20 for the 20 trials of them