Z-scores/table
What is the equation?
[ (x-bar) - M ] / (Sx/(sqrt n)
What is the equation?
[ (x-bar) - M ] / (Sx/(sqrt n)
Claim: 30 students bring an outside date to dances every year.
The average number of students who brought an outside date to dances this year was 26. Standard deviation was 3. All 175 students were included.
Create a 90% confidence interval for this data.
25.627-26.373
REJECT CLAIM
What are the symbols for null hypothesis and alternate hypothesis?
Ho and Ha
The average temperature in the summer is 74 degrees, Emily believes that the average temp is 68 degrees, what is the Ho and Ha?
Ho= 74 Ha= m<74
The average amount of shoes a person has is 6. Karen believes the average is 4 shoes. What is the Ho and Ha?
Ho= 6 Ha= m< 6
Claim: 5 donuts are eaten by Treetown PD members per day
The average number of donuts eaten by Treetown PD members per day was 3. Standard deviation was 2. All 50 members of the departments were included
Create a 95% confidence interval for this data.
2.45-3.55, REJECT claim
Claim: High school students sleep for an average of 6 hours per night.
Ho: M= 6
Ha: M>6
x bar: 6.3
Sx= 3.6
ACCEPT Ho, there is evidence to say that high school students sleep for an average of more than 6 hours per night.
If m=2 and x-bar= 1.54 and Sx= 2 and n= 50 then what is the z-score?
-1.61
If m= 7 and x-bar= 7.5 and Sx= 1 and n=24 what is the t-score
2.44
Claim: 39 birds visit Mia’s birdhouse every day.
The average number of birds who visited Mia’s birdhouse every day over the course of the month was 40.7 birds. Standard deviation was 10.4. All 42 birds in her house were included.
Create an 80% confidence interval for this data
38.6-42.7, DON’T REJECT
Claim: The participants with healthy color vision will score a 15 on the test.
Ha: M<15
Sx: 3.6
x bar: 12
REJECT Ho, there is evidence to say that the average score for participants with healthy vision is less than 15.
A company claims the average cost of bread is $5.00. A survey sampling 70 bakeries says the average cost of bread is $4.50 with a standard deviation of 1. Should you reject or don’t reject the null hypothesis based on the z-score?
Don’t Reject
The average Pardis Sabeti video is roughly 180 seconds long. However Elizabeth was skeptical and decided to keep track of the runtime for the next 10 Pardis Sabeti videos. Elizabeth found that the average runtime for a Pardis Sabeti video was actually 130 seconds with a standard deviation of 30. What is the t-value?
12.64
Claim: 170 WHS students participated in more than 2 sports this year
The average number of WHS students participated in more than 2 sports this year was 179. Standard deviation was 10. All 500 WHS students were included.
Create an 60% confidence interval for this data
178.89 - 179.1, REJECT CLAIM
Claim: The average drama movie is 125 minutes long. Karen found evidence to say that the average drama movie is less than 125 minutes long. What is the Ho and the Ha?
Ho: M=125
Ha: M<125
On average Mr. Wolf draws on the smart board with the wrong marker, 3 times. Mr. Spillane observed 20 days of classes and claims that it is an average of 5 times with a standard deviation of 1. Should you reject the null hypothesis based on the z-score?
Don’t reject
What year did Mr. Spillane start teaching at WHS?
2003
z=1.645
What is the z-score equation
z=(x bar - M)/(Sx/square root of n)