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Vocab
Z or t?
Margin of Error
CI
Whatevs
100
This can be found by dividing the sample standard deviation by the square root of the sample size.
Standard Error
100
What parameter MUST be present in order for me to use a Z-confidence interval for means?
Population standard deviation or sigma
100
Which two do I need to find Margin of Error: statistic, critical value, standard error, population size.
critical value and standard error
100
If (99.8, 104.6) is a 90% confidence interval for a sample of fifteen basketball scores, what is your conclusion about the average scores of the population?
We are 90% confident that the interval contains the population mean basketball scores.
100
What is the critical Z-value for a 95% confidence interval
1.96
200
This is any number that describes the population.
Parameter
200
Which of these changes when I use a t-distribution as opposed to a Z-distribution: Sample size, confidence level, or critical value?
critical value
200
If the standard error of a sample is 2.3 and the critical value for a confidence level is 3.456, what is the margin of error?
7.9488
200

If a confidence interval is from 26.32% to 35.85%, what is p-hat?

31.085% or 0.31085

200
If my sample size is 12, how many degrees of freedom are there?
11
300
This is built around a statistic in an effort to better approximate a population parameter.
Confidence Interval
300
Should I use a t-distribution or a z-distribution? Suppose that you want to find out the average weight of all players on the football team at a particular College. You are able to select ten players at random and weigh them. The mean weight of the sample of players is 198 lbs, with a standard deviation of 11.50 lbs.
t
300
Find the Margin of Error for a 95% z-confidence interval with a standard error of 4.2
8.232
300
The average heights of a random sample of 400 people from a city is 1.75 m. It is known that the heights of the population are random variables that follow a normal distribution with a standard deviation of 0.4 m. Determine the interval of 95% confidence for the average heights of the population.
n = 400 x = 1.75 σ = 0.4 c = 0.95 z* = 1.96 (1.75 ± 1.96 • 0.4/20 ) → (1.7108, 1.7892)
300
If my t-value is 2.518, what is the required confidence level and sample size?
C=0.99 or 99%; n=22
400
This is added and subtracted from the statistic in order to construct a confidence interval
Margin of Error
400
Should I use a t-distribution or Z? The average heights of a random sample of 400 people from a city is 1.75 m. It is known that the heights of the population are random variables that follow a normal distribution with a standard deviation of 0.4 m. Determine the interval of 95% confidence for the average heights of the population.
Z
400
What is the margin of error for a sample with a critical value of 1.76, a sample size of 64, and a sample standard deviation of 3.5?
0.77
400
Suppose that you want to find out the average weight of all players on the football team at a particular College. You are able to select ten players at random and weigh them. The mean weight of the sample of players is 198 lbs, with a standard deviation of 11.50 lbs. Construct a 90 percent confidence interval for the population weight, if you presume the players' weights are normally distributed.
(192, 204)
400
Why are confidence intervals necessary?
Because the statistic is not a very good approximation for the population parameter.
500
This is the number of free choices allowed by my parameter.
Degrees of freedom
500

What type of interval should I use? 68% of pizzas were ordered with pepperoni as a topping in a random sample of 40 orders from a local pizza place. Determine the interval of 95% confidence for the proportion of all pizzas that are ordered with pepperoni as the topping.

1 proportion z-interval
500
If the margin of error of a sample is 3.45, the sample size is 16, and the critical value for the confidence level is 1.876, then what is sample standard deviation?
7.356
500
If a sample of 36, has a mean of 29, and a standard deviation of 4.3, find a 90% confidence interval for the population mean.
(28.055,29.945)
500
DAILY DOUBLE: When is Pi Day?
March 14 (3.14)