Terms
A range of values used to estimate the true value of a population parameter
Confidence interval
What is the best point estimate of the population proportion p?
Sample proportion or p hat
What is the best point estimate of the population mean "u"?
The sample mean or x bar
What is the best point estimate of the population variance?
Sample variance or s2
A critical value of 1.96 has what confidence level?
95%
A single value or point that is used to approximate a population parameter
Point estimate
What is the critical value za/2 corresponding to a 99% confidence level
2.575
If the sample size is 2024, how many degrees of freedom are there?
2023
n-1
What type of distribution does Chi-Square have?
Non-symmetric
Right skewed
What does (n -1)s2 divided by the variance "o2" give you?
The sample statistic for a Chi-Square distribution
The probability that the confidence interval actually does contain the population parameter
Confidence level
If the confidence level of something is 67%, what is the value of the fancy "a"
0.33 or 33%
A confidence interval for estimating a population mean has some requirements that need to be fulfilled.
One of them is it being a simple random sample
The other is that the population is normally distributed, or the same size is what?
n > 30
What type of distribution must there be in order to create a confidence interval for estimating a population standard deviation or variance
Normal
Very Strict
If no estimate for p hat is known, what are we forced to assume it is?
0.5
The maximum likely difference between the observed sample proportion and the true value of population proportion
Margin of error
What is za/2 times the square root of (p hat times q hat) divided by n give you?
*Draw it*
Margin of error for proportions
Which of the following interpretations is correct?
1) "We are 95% confident that the interval from 58.1 to 63.3 actually does contain the true value of u"
2) "There is a 95% chance that u will fall between 58.1 and 63.3"
1
To be 99% confident that s is within 20% of the value of the standard deviation, the sample size should be at least what number
85
What does za/2 times standard deviation over the square root of n give you?
Margin of error for a mean
The name for the number on the borderline separating sample statistics that are likely to occur from those that are unlikely
Critical value
Calculate the margin of error for a proportion with a critical value of 1.96, a p hat value of 0.85, a q hat 0.15, and n is 1007.
Once you have the margin of error, write your answer in terms of a confidence interval rounded correctly.
0.828 < p < 0.872
*Page 332*
FINAL JEOPARDY
Confidence is Key
Find the X2 critical value for the right tail and left tail for a simple random sample of 22 subjects with a 95% confidence interval.
10.283 and 35.479
*Page 363*
What is the basic setup for a confidence interval for u (population mean) that involves inequality symbols?
Make sure to use the correct symbols and variables.
x - E < u < x + E