Vocabulary
Inference
What is the process of drawing conclusions about a population on the basis of sample data
The percentage of data greater than a z-score of 2.4?
What is 0.82%
The formula for the margin of error
What is z*(σ/sqrt(n))?
You have a z-score of 2.5 and your alpha level is 0.01, can you reject the null hypothesis if it is a two-tailed test?
No, p=0.0124 which is greater than 0.01
A numerical characteristic of a population, such as the population mean or population standard deviation
What is a parameter?
Suppose that blood sugar levels are normally distributed with a mean of 100 mg/dl (milligrams per deciliter) and a standard deviation of 10mg/dl. David has a blood sugar level of 85 mg/dl. Calculate David's z-score.
What is z=-1.5
The upper limit of a 90% confidence interval of the trunk length of elephants if a study of 100 elephants has a sample mean of x̄=7ft with a standard deviation of σ=1ft
What is 7.1645
Test scores are normally distributed with a mean of 85% and a standard deviation of 5.4%. You believe people who went to tutoring did significantly better. There are 100 kids who went to tutoring and their mean score was 89.7%. Write out the null and alternative hypotheses.
Ho: µ=85 Ha: µ>85
What is the set of all possible outcomes
The maximum weight a pumpkin can be and still be in the lower 16% of the weight of all pumpkins if the weight of pumpkins is normally distributed with μ=100 and σ=25lb.
What is 75lb?
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
What is one states that a parameter is larger than or smaller than the null hypothesis, and the other states the parameter is different than the null hypothesis
Weights of babies are approximately normal with μ = 7.7 pounds and σ = 1.1 pounds, N(7.7, 1.1). What weight would put a newborn baby in the 95th percentile?
What is 9.51 pounds?
The margin of error for a 90% confidence interval where the mean is 5.4, the standard deviation is 1.1, and the sample is 16 individuals
What is 0.452?
You run an experiment to see if your sample is significantly shorter than the US population. Your sample has a mean height of 65.9in. The population has a mean height of 67.1in and a standard deviation of 2.1in. Is your sample significantly shorter at the 0.05 level? (n=16)
Yes, p=0.0111 therefore it is statistically significant