Transcript Statistics Class 21

Statistics Class 21
4/23/2012
Quiz 17
When 40 People used the Weight Watchers diet
for one year their mean weight loss was 3.0 lb.
Assume that the standard deviation of all such
wight changes is 𝜎= 4.9 lb and use a 0.01
significance level to test the claim that the
mean weight loss is greater than 0. Based on
these results does the diet appear to be
effective? Does the diet appear to be practical?
𝑥 − 𝜇𝑥
𝑧= 𝜎
𝑛
Testing a Claim about a Mean: 𝜎 Known
We first need to make sure we meet the requirements.
1. The sample observations are a simple random sample.
2. The value of the population standard deviation 𝜎 is known
3. Either the Population is normal, or 𝑛 > 30
Test Statistic for Testing a Claim about a Proportion
𝑥 − 𝜇𝑥
𝑧= 𝜎
𝑛
Lets do some examples then, onto the 8-4 Worksheet!
Testing a Claim about a Mean: 𝜎 not Known
We first need to make sure we meet the requirements.
1. The sample observations are a simple random sample.
2. The value of the population standard deviation 𝜎 is known
3. Either the Population is normal, or 𝑛 > 30
Test Statistic for Testing a Claim about a Proportion
𝑥 − 𝜇𝑥
𝑡= 𝜎
𝑛
Lets do some examples then, onto the 8-5 Worksheet!
Testing a Claim about a St.Dev or Variance
We first need to make sure we meet the requirements.
1. The sample observations are a simple random sample.
2. The population has a normal distribution.
Test Statistic for Testing a Claim about a 𝛔 or 𝝈𝟐 .
2
(𝑛
−
1)𝑠
𝜒2 =
𝜎2
Lets do some examples then, onto the 8-6 Worksheet!
Basics of Hypothesis Testing
Homework!!
8-4: 1, 3, 7-17 odd
8-5: 1-7 odd, 13-27 odd
8-6: 1-19 odd