Chi-Square!!

If the p-value is less than α, we reject H₀

• True
• False

A hypothesis test is performed and
p-value = 0.02. Which is the best conclusion?

• H₀ is rejected at α = 0.01.
• H₀ is rejected at α = 0.05.
• Ha is rejected at α = 0.01.
• Ha is rejected at α = 0.05.

Which of the following is the FIRST step of a hypothesis test?

• Check assumptions & conditions
• Find your test statistic
• State your conclusion
• State your null & alternative hypotheses

Observed in the wild are 10 circles, 20 squares and 30 triangles. The ratio for this particular population is 2:3:5 
observed: 10 circles     expected: 12
observed 20 squares    expected : 18
observed 30 triangles   expected: 30
What is the degrees of freedom?

• 1
• 2
• 3
• 4

What are the degrees of freedom for the following χ² test?

• 6
• 2
• 5
• 36

Tags

CCSS.HSS.CP.A.4

What are the degrees of freedom?

• 3
• 2
• 1
• 9.488

The purpose of randomization is to reduce

• blinding
• bias
• confounding
• variability

Tags

CCSS.HSS.IC.B.3

What are the expected counts of a female who likes Pepsi?

• 10.5
• 11
• 14.5
• 6.3

Tags

CCSS.HSS.CP.A.4

CCSS.HSS.ID.B.5

CCSS.HSS.MD.A.2

What is the expected value for all cells, if we assume that this is a fair six sided die?

• 96
• 16
• 8
• 1/6

Tags

CCSS.HSS.MD.A.2

CCSS.HSS.MD.A.3

CCSS.HSS.MD.B.5

Here is a two-way table of counts. The expected counts are in red. The data are based on an SRS with two categorical variables.  Is it safe to use the chi-square test with critical values from the chi-square distribution?

50 51.35 36 31.65 12 14.99
16 18.34 13 11.31   6 5.36
 54 50.30 25 31.01 17 14.69

• Yes because all of the observed counts are 5 or greater
• b)Yes because all of the expected counts are 5 or greater.
• c)No because the expected counts are not whole numbers.
• d)Yes because the sum of observed counts = sum of  expected.