Chapter 7

Question 1

Estimation

Answer 1

Process of estimating the value of a parameter from information obtained from the sample

Question 2

Estimators

Answer 2

Sample measures- used to estimate population measures
Sample Proportion- used to estimate population proportion.

Question 3

Point Estimate

Answer 3

A specific numerical value estimated of a parameter. The best point estimate of the population mean is the sample mean

Question 4

Interval Estimate

Answer 4

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 5

Properties of a good estimator

Answer 5

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 6

Confidence Level

Answer 6

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 7

Confidence Interval

Answer 7

A specific interval estimate of a parameter determined by using data obtained from a sample and by using the specific confidence level of the estimate

Question 8

Margin of Error

Answer 8

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 9

Normalcdf

Answer 9

Used to find the probability or area under the curve

Question 10

Invnorm

Answer 10

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 11

Best Point Estimate of a Population Mean

Answer 11

Is the sample mean

Question 12

Confidence intervals

Answer 12

90% – 1.65
95% – 1.96
99% – 2.58

Question 13

Assumptions for finding confidence interval for mean when population standard deviation is known

Answer 13

1. Sample is a random sample
2. Either n>30 or population is normally distributed when n<30

Question 14

Sample size depends on

Answer 14

1. Margin of error
2. Population standard deviation
3. Degree of confidence

Question 15

Confidence interval for mean can be found with z distribution when

Answer 15

1. Population standard deviation is known & sample size is 30 or more
2. If sample size is less than 30, the population is normally distributed

Question 16

T-distribution

Answer 16

Shares some characteristics of the standard normal distribution and differs from it in others

Question 17

Degrees of Freedom

Answer 17

Number of values that are free to vary after a sample statistic has been computed

Question 18

Assumptions for finding a confidence interval for mean when population standard deviation is unknown

Answer 18

1. Sample is a random sample
2. Either sample is greater than or equal to 30 or the population is normally distributed when n<30

Question 19

Proportion

Answer 19

Represents a part of a whole
- can be expressed as a fraction, decimal, or percentage
- Proportions also represent probabilities

Question 20

Serenity

Answer 20

What the probability is called

Question 21

3 Properties of a good estimator

Answer 21

1. Unbiased
2. Consistent
3. Relatively efficient

Question 22

Assumptions for Finding Confidence Interval for a Population Proportion

Answer 22

1. Sample is a random sample
2. Conditions for a binomial experiment are satisfied