Chapter 7

Question 1

Which measures can be estimated from sample data?

Answer 1

• The mean (most common)
• ANY SAMPLE STATISTIC (variance, skewness)
  Anything that you can measure from sample data

Question 2

What does estimation mean?

Answer 2

An educated guess on population parameters based on sample statistics

Question 3

What are point estimates?

Answer 3

a single value is given for the population parameter. IT IS THE SAMPLE MEAN

Question 4

What are confidence intervals?

Answer 4

a range of values that is given for the parameter (percent ranges) 2 values usually

Question 5

When do you use point estimates?

Answer 5

when you want to be more precise and want a single value

Question 6

When do you use Confidence intervals?

Answer 6

when you want to be more accurate and have a range of things

Question 7

Explain point estimates in regards to precision and accuracy

Answer 7

It is the most precise estimate because it is infinitely narrow
But it is the least accurate because it has low odds of including the true population value

Question 8

Explain confidence intervals in regards to precision and accuracy

Answer 8

Increases accuracy by having a range of values. Doesn’t have good precision but they are more helpful
Confidence means that whatever percent of the range will have the population mean in it

Question 9

How doe n (sample size) affect point estimate?

Answer 9

n (sample size) DOES NOT affect the point estimates

Question 10

How doe n (sample size) affect confidence intervals?

Answer 10

Larger n (sample sizes) The more narrower/shorter they will be. (more precise and more accurate)
The smaller the n (sample sizes) the more wide/taller they are (less precise and less accurate)

Question 11

How do you calculate the point estimate?

Answer 11

NO CALCULATIONS NEEDED IT IS THE SAMPLE MEAN

Question 12

How do you calculate the confidence intervals for a sample?

Answer 12

The mean minus the z score times the standard deviation (need to calculate the standard deviation first SD/the smple size (n) squared)

Question 13

How do high and low confidence levels affect the width of confidence intervals?

Answer 13

Higher confidence levels (98%, 99%) the more width/height the confidence interval has

Lower confidence levels (90%, 9%) it causes narrower (less wide/shorter) confidence intervals

Question 14

How do high and low Standard deviations levels (SD) affect the width of confidence intervals?

Answer 14

Larger/greater standard deviations lead to more wide confidence intervals (more width/taller)

Lower/lesser standard deviations lead to more narrower (less wide/shorter) confidence intervals

Question 15

How do the high and low Sample Sizes (n) affect the width of confidence intervals?

Answer 15

Large sample sizes will lead to narrower (less wide/short)

Smaller sample sizes will lead to conference intervals that are wider/taller

Question 16

How do you tell which of two samples have a larger or smaller n based on the width of the confidence interval?

Answer 16

Higher confidence levels (taller/more width) = small n value

Lower confidence levels (shorter/less width) = higher n value