There is a relationship between confidence interval and standard deviation:

Where

is the mean,

is standard deviation, and n is number of data points.
Every confidence interval has associated z value. This can be found online.
We need to find the standard deviation first:

When we do all the calculations we find that:

Now we can find confidence intervals:

We can see that as confidence interval increases so does the error margin. Z values accociated with each confidence intreval also get bigger as confidence interval increases.
Here is the link to the spreadsheet with standard deviation calculation:
https://docs.google.com/spreadsheets/d/1pnsJIrM_lmQKAGRJvduiHzjg9mYvLgpsCqCoGYvR5Us/edit?usp=sharing
Answer:
The fraction of the students who failed to went partying = 
Step-by-step explanation:
Let total number of students = 100
No. of students partied are twice the no. of students who not partied.
⇒ No. of students partied = 2 × the no. of students who are not partied
No. of students partied before the exam = 20 % of total students
⇒ No. of students partied before the exam =
× 100
⇒ No. of students partied before the exam = 20
No. of students who not partied before the exam = 
Thus the fraction of the students who failed to went partying = 
Answer:
(a)r=15-b
11.9 Inches
(b)See attached
Step-by-step explanation:
Length of the candle =15 inch
Let b represent the burned length of the candle (in inches)
Let r represent the remaining length of the candle (in inches).
Therefore:
(a) r+b=15
r=15-b
When b=3,1 Inches
Remaining Length, r=15-3.1=11.9 Inches
(b)The graph showing te relationship between r and b is shown below.
r is plotted on the y-axis while b is plotted on the x-axis as labelled.
Answer:
speed=225.75 miles per hour
Step-by-step explanation:
given:
s=301/2
t=2/3
we have,
v=s/t
v=(301/2)/(2/3)
=(301/2)×3/2
=903/4
v=225.75
therefore, speed of car will be 225.75 miles per hour