unit 7

Question 1

Differences that a t distribution has from a normal distribution

Answer 1

It’s shape, is the same but
- it has more varibaility, more areas in the tails

Question 2

relationship between Df and the t distribution’s tail

Answer 2

As Df increases, the area in the tails decrease and the t distrbution approaches the standard normal distribution. This is true as the value of Sx will be closer to the true standard deviaiton as the sample size increases

Question 3

Degrees of freedom formula

Answer 3

n-1

Question 4

Why is the critical value of T larger than z?

Answer 4

We need a critica; va;ue to be larger then z as it should compesnate the variability that is introduced by using sample standard deivation as an estimate for the population standard deviation.
- The larger critical value will make sure that the area stated by confidence level is captured.

Question 5

Steps for Confidence interval of mean

Answer 5

1. State; Parameters, Confidence level, DF, x̄, Sx
2. Plan
   - Random
   - 10%
   - n>/= 30 or boxplot/dotplot is approximatlely normal w/no extreme outliers
3. Do
   x̄ +- t* SD/√n
4. Conclude

Question 6

Concluding interval. interpreting interval

Question 7

Interpreting standard error

Question 7

Increasing the sample size (n) affects the Margin of error by…

Answer 7

decreasing it –> increases the number of people meaning less I ahve to wonder

Question 8

Increasing the confidence level affects the margin of error by…

Answer 8

Increasing it

Question 9

Bias affectd ME by..

Answer 9

does not fix it

Question 10

Margin of error accounts for…

Answer 10

only sampling variability

Question 11

Main Difference between paired tests and 2 sample t tests

Answer 11

How was data collected?

Question 12

Traits of paired t test

Answer 12

• Measures multiple things
• Has a difference column
• List can not be jumbled
• Same # of data points