T Significance Tests
Confidence Intervals
Z Significance Tests
QUICK CHECK
Misc Trivia
100
What table do we use to find critical values?
Table C
100
The formula for Margin of Error
What is z*(σ/sqrt(n))?
100
What is the assumed alpha level if not clearly stated in the problem?
0.05
100
A small p-value means that...
Strong evidence against the null hypothesis (aka rejecting it!) not likely to happen by chance
100
Who Plays Bella Swan in the Twilight Movie Series?
Kristen Stewart
200
The mean height of adult American males in 1912 was around 68.3 inches. A random sample of 11 adult men in 2015 yields a mean height of 69.7 inches with a standard deviation of 2.4 inches. At
alpha=0.1
is this data significant?
Yes
200
A peanut manufacturer wants to estimate the mean weight of their jar of peanuts. A sample of 60 jars is collected, and the sample mean weight is 3.2 pounds and a sample standard deviation of 0.21 pounds. The manufacturer wants a 95% confidence interval for the true mean weight of all if its peanut jars.
It is a T-Confidence Interval. What is [3.147,3.253]
200
Assuming we are running a 2-tailed z-test, what is the p-value when z=2.12?
p= 0.034
200
A test of H0 : μ = 1 against Ha : μ > 1 has test statistic z = 1.96
Is this test significant at the 5% level α = 0.05?
Is it significant at the 1% level α = 0.01?
p-value= 1-.975=.025 (Using Table A)
Significant at 5% level .025 is less than .05
Not Significant at 1% level .025 is greater than .01
200
What was the highest-grossing song of 2020?
"Blinding Lights" by The Weeknd
300
A researcher reads a paper introducing a new test of executive function. The authors of the paper had tested 30 healthy volunteers and found that on average they score 51 on the new test. The researcher believes that patients with schizophrenia will score less than the normal average on this test of executive function. They test 22 patients with schizophrenia. The average score for the patients is 39 with a standard deviation of 4.3. Is there significant evidence at the 5 % level to support the researcher’s claim?
13.090>1.721 so it is significant and it supports the researcher's claim
300
The margin of error for a 90% z confidence interval where the mean is 5.4, the standard deviation is 1.1, and the sample is 16 individuals
What is 0.452?
300
The time it takes to download a video game is normally distributed with µ=2 hrs and σ=1hr. Dave believes it takes longer than 2 hrs to download a video game and so he randomly downloads 20 video games and finds the average time it takes to download a video game to be 2 hours and 30 minutes. What is the null hypothesis, alternative hypothesis, P-value, and statistical significance of the P-value at a significance level of α=.01
Ho: µ=2hrs, Ha: µ>2hrs, P=.0127, Not statistically significant and can not reject null hypothesis
300
Critical t Value for 80% if your sample is 25 people
What is 1.318
300
What is Professor Hayden Harker's favorite sport (he also coaches a team in Eugene)?
Ultimate Frisbee
400
A psychology student, Sarah, is giving out sleep diaries to her university friends to monitor the number of hours of sleep they have each night. Sarah believes that university students sleep for 6 hours per night on average. Below is the data that they collected. The number of hours sleep per night for each student was averaged over a one month monitoring period. Is there any evidence to suggest that Sarah’s belief is incorrect?
0.8115<2.262, so it is NOT significant
400
The sample size that gives a margin of error of at least 1.2 for a study of the weights of narwhals that has a sample mean of x̄=1200 and a standard deviation of σ=40lbs with a confidence level of 99%
What is 7374 narwhals?
400
Suppose we randomly sampled 25 subjects from an honors program. We want to determine whether their mean IQ score of 107 differs from the general population when alpha is 0.025. The general population’s IQ scores are defined as having a mean of 100 and a standard deviation of 15.
p=0.198 < 0.025, so they do differ significantly
400
You have a t-value of 2.32 from a sample of 15 people and you want to know if it is significant if you have a 1-tailed alpha level of 0.01
No it is not significant, 2.32<2.624
400
What is the following bone & feature of the bone?
Dorsal Tubercle of the radius