Exam 3 Terms

Question 1

Sampling Error

Answer 1

The difference between the sample measure and the corresponding population measure due to the fact that the sample is not a perfect representation of the population

Question 2

Sampling distribution of sample means

Answer 2

A distribution using the means computed from all possible random samples of a specific size taken from a population.

Question 3

Central Limit Theorem

Answer 3

As the sample size increases without limit, the shape of the distribution of the sample means taken with replacement will approach a normal distribution

Question 4

Properties of a Good Estimator

Answer 4

1. Unbiased- the expected value or the mean of the estimates from samples is equal to the parameter being estimated.
2. Consistent estimator- As sample size increases, the value of the estimator approaches the value of a parameter estimated
3. Relatively Efficient Estimator- Of all the statistics that could be used to estimate the parameter, the relatively efficient estimator has the smallest value.

Question 5

Margin of Error

Answer 5

Also called the maximum error of the estimate, is the maximum likely difference between the point estimate of a parameter and the actual value of the parameter

Question 6

Normalcdf

Answer 6

Used to find the probability or area under the curve

Question 7

Invnorm

Answer 7

Used to find the z-value (or value in the context of an application problem, such as, finding the length, height, salary, score, or price…)

Question 8

Confidence intervals

Answer 8

90% – 1.65
95% – 1.96
99% – 2.58

Question 9

Interval Estimate

Answer 9

A parameter is an interval, or a range of values used to estimate the parameter. This estimate may or may not contain the value of the parameter being estimated

Question 10

Confidence Level

Answer 10

Interval estimate of a parameter is the probability that the interval estimate will contain the parameter, assuming that a large number of samples are selected and that the estimation process on the same parameter is repeated

Question 11

Properties of a Normal Distribution

Answer 11

-Bell-shaped curve
-The total area under the normal distribution curve is 1.00
- The area under the part of a normal curve that lies within 1 standard deviation of the mean is approximately 0.68
- The area under the part of a normal curve that lies within 2 standard deviations of the mean is approximately 0.95
- The area under the part of a normal curve that lies within 3 standard deviations of the mean is approximately 0.997
-The mean, median, and mode are located at the center of the distribution
- The normal distribution curve is unimodal

Question 12

The difference between a sample mean and the population mean may be referred to as _____.

Answer 12

Sampling error

Question 13

The Central Limit Theorem states that as the sample size n ______, the shape of the distribution of the sample means taken with replacement from a population with mean “mew” and standard deviation “sigma” will approach a normal distribution.

Answer 13

Increases

Question 14

The term zx/2(sigma/square root of n) represents the ________.

Answer 14

Margin of error

Question 15

Which is not a property of a good estimator?

Answer 15

Accurate

Question 16

What value is used in the 95% confidence interval of a normal distribution?

Answer 16

1.96

Question 17

True or false, the t-distribution must be used when the population standard deviation is known.

Answer 17

False

Question 18

t-distribution

Answer 18

Used when population standard deviation is unknown.

Question 19

Z-interval

Answer 19

Used when population standard deviation is known.

Question 20

1-probZInt

Answer 20

Used to estimate proportions

Question 21

Z-interval

Answer 21

Used when population standard deviation is known