Confidence Intervals/Point Estimators (7A)
The _____ of roe and alpha must equal 1
sum
What value of n must be met to satisfy the Central Limit Theorem?
30
T or F
If we are determining the probability of the sample mean exceeding a value x, we use the compliment rule.
True
T or F
If roe = 80%,
alpha/2 = ______
10%
T or F
The t-distribution is wider than the z-distribution
True
If you are 95% confident, what is the value of alpha?
5%
T or F
According to the Central Limit Theorem, if all requirements are satisfied, the distribution would approximate a(n) ________ distribution.
Normal
T or F
If we are determining the probability of the sample mean below a value x, we use the compliment rule.
False
p* represents ______ data
historical
n-1 is used to determine
degrees of freedom
Given [0.7, 0.8]
What is the value of E?
0.05
Suppose n=20 and samples are taken from a known normal population distribution. The distribution will be _______
a) normal
b) cannot be determined
A
Suppose a number of car parts have a mean of 110cm and a standard deviation of 6cm. If 5 parts are chosen, what is the probability that the mean exceeds 111cm?
35.57%
Determine the sample size required to estimate a population mean within 5 units given that the population standard deviation is 15. Use a confidence level of 98%.
49
We use the t-distribution when _______ is unknown
Standard deviation
If the sample has 500 votes, what x value gives the sample proportion a value of 40%
200
Suppose n=31 and samples are taken from an asymmetric distribution. The distribution will be ______
a) normal
b) cannot be determined
A
Suppose a proportion of students who will go home for Thanksgiving is assumed to be 76%. What is the probability that in a sample of 300 voters, less than 70% say they will go home for Thanksgiving?
.75%
The population proportion is 65%. Determine the sample size required if we want our poll to have a margin of error of 4% with a 99.9% confidence interval.
1540
Suppose n=50 and we want to be 99% confident. Find the t-value.
2.68