sampling inference parameter

Question 1

what is the area under the curve of a normal distribution ?

Answer 1

1 which is equal to the sum of all the possibilities/probabilities

Question 2

μ ± 1σ includes how much of the population ?

Answer 2

68%

Question 3

μ ± 2σ includes how much of the population ?

Answer 3

95.4%

Question 4

μ ± 3σ includes how much of the population ?

Answer 4

99.7%

Question 5

what is statistical inference ?

Answer 5

is the conclusion we reach about a population based on data collected about a certain sample

Question 6

what are measurements in a population called ?

Answer 6

parameters

Question 7

what are measurements in a sample called ?

Answer 7

statistics

Question 8

what are the two methods of making statistical inference ?

Answer 8

1. point and interval estimation

2. hypothesis testing

Question 9

what is a point estimate ?

Answer 9

a single numerical value ues to estimate the population parameter

Question 10

what is an interval estimate ?

Answer 10

consists of two numerical values defining a range of values, with a specified degree of confidence

Question 11

what is the best point estimate of the population parameter ?

Answer 11

sample statistic

Question 12

what is the CI ?

Answer 12

gives info about closeness to the unknown population parameter

Question 13

what is random error ?

Answer 13

an error resulting from the process of sampling

Question 14

what is an example of the sample error ?

Answer 14

different samples with the same sample size will give different estimates for the population parameter

Question 15

what is the difference between the standard error and the standard deviation ?

Answer 15

standard deviation applies to a single sample

standard error applies to multiple samples

Question 16

what is the central limit theory ?

Answer 16

the average of a random sample will more closely resemble the average for the whole population as the sample size increases regardless of the shape of the distribution

Question 17

what is the standard error ?

Answer 17

its the standard deviation divided by the square root of the population

Question 18

how is the 95% CI calculated ?

Answer 18

multiply the SE by 1.96

use that answer to add and subtract from the mean to get the upper and lower limit of the confidence interval

Question 19

how is the population mean or the confidence interval calculated ?

Answer 19

μ = x ± Z × SE mean.

Question 20

how is the z score calculated ?

Answer 20

x - u
____
SD

Question 21

what is the relationship between the sample size and the standard error ?

Answer 21

as sample size increases the standard error decreases and the confidence interval becomes smaller

Question 22

what is the variable is not normally distributed in the population ?

Answer 22

if the sample size is equal to or above 30 then the central limit theory still applies

Question 23

if the standard deviation of the population os not known and we have to use the sample’s standard deviation what value must replace the z value ?

Answer 23

the t value

Question 24

how is the degree of freedom for the t table calculated ?

Answer 24

n-1

Question 25

what is the standard error of qualitative variables ?

Answer 25

square root of :
p(1-p)
_____
n

Question 26

does a wide CI have any significance ?

Answer 26

none