Question

1. A polling firm finds that 58% of the population of a state favors legalizing the use of marijuana. The margin of error of the poll is 4%.
If the confidence level is 95% then about how many people were polled? Round up.

Select one:
a. 394
b. 294
c. 625
d. 518
e. None of these

2. At the 95% confidence level, what is the margin of error of a poll of 600 people?

Select one:
a. 2.47%
b. 4.08%
c. 3.47%
d. 95%
e. 9.7%

3. If two events are negatively correlated, then one of them must have caused the other.
Select one:
True
False

4. A clinical trial for an experimental treatment for acne has a p-value of 0.04. Mark the following statement true, or false.

96% of the patients treated must have improved.

Select one:
True
False

5. A clinical trial for an experimental treatment for acne has a p-value of 0.04. Mark the following statement below true, or false.

The result is statistically significant.

Select one:
True
False

6. The weights of oranges in a harvest are normally distributed, with a mean of 150 grams and standard deviation of 10 grams. What percent of for such oranges weighing less than 160 grams.

Select one:
a. 160%
b. 15.87%
c. 150%
d. 84.13%

7. Find the standard deviation of the following numbers. Round to the nearest hundredth.
4, 8, 9, 11, 12

Select one:
a. 2.79
b. 6.71
c. 1.89
d. 2.17
e. 4.53

8.Fill in the blanks:

In a drug study, some people get the drug, and some do not. Those who do not get the drug are called -------- group.
Select one:
a. treatment
b. control
c. None of these
d. correlation
e. double-blind

9. Your SAT score is in 70th percentile", this means that your SAT score is higher than 30% of SAT test takers
Select one:
True
False

10. A clinical trial for an experimental treatment for acne has a p-value of 0.04. Mark the following statement below true, or false.

The chance that as many or more patients would have improved without treatment is under 4%.

Select one:
True
False

11. The confidence interval for a poll is 52% to 60%. What is the margin of error?

Select one:
a. 96%
b. 13.5%
c. 55%
d. 6%
e. 4%

12. A polling firm finds that 58% of the population of a state favors legalizing the use of marijuana. The margin of error of the poll is 4.5%.

What is the confidence interval of the result?

Select one:
a. 55% to 61%
b. 49.55 to 59.5%
c. None of these
d. 57.5% to 58.5%
e. 53.5% to 62.5%

Answer 1

1)

sample proportion ,   p̂ =    0.58                          
sampling error ,    E =   0.04                          
Confidence Level ,   CL=   0.95                          
                                  
alpha =   1-CL =   0.05                          
Z value =    Zα/2 =    1.960   [excel formula =normsinv(α/2)]                      
                                  
Sample Size,n = (Z / E)² * p̂ * (1-p̂) = (   1.960   /   0.04   ) ² *   0.58   * ( 1 -   0.58   ) =    584.8621
                                  
                                  
so,Sample Size required=       585                          

answer: NONE OF THESE

===========

11)

confidence interval is                  
lower limit =    0.52       upper limit=   0.6  

margin of error = (upper limit-lower limit)/2= (   0.52   -   0.6   ) / 2 =   0.04 or 4%

12)

Interval Lower Limit = p̂ - E = 58-4.5 =  53.5%
Interval Upper Limit = p̂ + E = 58+4.5 =62.5%

e. 53.5% to 62.5%