Confidence Interval
The formula for a confidence interval.
What is x̄±z*(σ/sqrt(n))?
The most commonly used significance levels
What is α=.01 and α=.05?
The major difference between the formulas for a population distribution and a sampling distribution
What is dividng the standard deviation by the sqrt(n)?
The importance of using a random sample
What is, it eliminates bias in the act of choosing a sample?
The formula for the margin of error
What is z*(σ/sqrt(n))?
The meaning of P being less than alpha
What is "the experiment failed to reject the null hypothesis"?
The sample standard deviation if the height of palm trees is normally distributed with µ=40ft and σ=15ft and a sample of 45 palm trees is selected.
What is 2.24ft?
The sample space of flipping a double sided coin 5 times
What is 32?
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?
A study is done that determines the length of geckos to be normally distributed with µ=7in and a standard deviation of 2in. Amanda believes the mean length of geckos is less than 7in and conducts her own study where she randomly measures 40 geckos and finds their mean length to be 6 inches. What is the null hypothesis, alternative hypothesis, P-value, and statistical significance of the P-value at a significance level of α=.05.
Ho: µ=7in, Ha: µ>7in, P=.008, Statistically significant and reject null hypothesis
The z-score of rhinos that have horns so long that only 33% of rhinos have longer horns, if the the length of rhino horns is normally distributed with µ=10in and σ=2in and 100 rhinos had their horns measured.
What is z=.44?
The probability that a randomly chosen person’s phone takes exactly 6 hours to charge if the time it takes for people’s phones to charge is normally distributed with µ=2hrs and σ=30minutes.
What is 0%?
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 7.1645ft?
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=.0125, Not statistically significant and can not reject null hypothesis
The z-score of individuals that have a weight of 150lbs or less if the weight of people is normally distributed with µ=180lbs and σ=25lbs if 10 individuals are randomly selected and weighed.
What is z=-3.79?
The probability of rolling two 6 sided die and getting sums of 4, 5, 8, 11, and 12.
What is .4167?
The approximate sample size of a study of the time it takes hippos to walk up a hill if there is a 95% confidence interval of 7 minutes to 10 minutes with a standard deviation of σ=500 seconds
What is 119 hippos?
The weight of koalas is normally distributed with µ=20 lbs and σ=6lbs. Steve believes the average weight of koalas does not equal 20lbs. He measures the weights of 30 randomly selected koalas and finds their mean weight to equal 18lbs. What is the null hypothesis, alternative hypothesis, P-value, and statistical significance of the P-value at a significance level of α=.05.
Ho: µ=20lbs, Ha: µ≠20lbs, P=.0672, Not statistically significant and can not reject null hypothesis
The number of teeth that the top 20% and bottom 20% of sharks have if the number of teeth sharks have is normally distributed with µ=200 and σ=25 if a sample of 13 sharks is randomly selected.
What is 194.16 and 205.86?
The probability that a randomly selected person listens to 9 hours to 13 hours of music or 1 hours to 2 hours of music if the amount of time people spend listening to music every week is normally distributed with µ=10hrs and σ=3hrs.
What is .4744?