Unit 5

Question 1

What is a parameter and symbols

Answer 1

Measure of the population

mew = mean
p = proportion

Question 2

What is a statistic
what is it used for
symbols

Answer 2

A point estimator of the corresponding population parameter

Make inferences about the population through measures in the sample.

x bar = mean
p hat = proportion

Question 3

2 properties of samples

Answer 3

Diff samples from the same population produce the same statistic

If the distribution of a population is known, then the distribution of statistics from many random samples of the same size from that population is predictable.

Question 4

How to find the probability of an event happening using calc if yk mean and sd

Answer 4

NCD(var, LB, UB, s/d, mean)
if ur using z score
NCD(var, LB, UB, 1, 0)

Question 5

Characteristics of a approx norm dist

Answer 5

Unimodal, roughly symmetrical, bell shaped

Empirical rule general applies

Question 6

What does the CLT state

Answer 6

The central limit theorem states that when the sample size is sufficiently large, a sampling dist of the mean of the random variable will be approx norm dist.

if n>= 30 then approx norm dist

Question 7

What is the sampling dist for a statistics

Answer 7

Distribution of a value for the statistic of values for the statistic for all possible samples of the same size from a given population

Question 8

When is the sampling dist for the sample prop approx norm

Answer 8

np >= 10 and nq >= 10

q = (1-p)

Question 9

How to interpret mean of sample prop

mew of p hat

Answer 9

For all random samples of size n = ‘’ from this population, the sample proportions of ‘population’ who have ‘sample’ will have a mean of ‘’.

Question 10

How to interpret s/d of phat dist

Answer 10

For all random samples of size n = ‘’ from this population, the sample proportions of ‘population’ who have ‘sample’ typically vary by about 0.065 from the population proportion of ‘0.3’

Question 11

How to interpret a probability (1 proportion)

Answer 11

Getting a sample proportion of ‘’ or less/more happens only about ‘’% of the time of all possible sample of sizes ‘’ from this population. Very usual/unusual

Question 12

How to interpret the MEAN of DIFF IN PROP

Answer 12

For all random samples of ‘50 students’ from ‘high school A’ and ‘50 students’ from ‘high school B’, the differences (‘A-B’) in sample proportions of ‘students who have a driver’s license’ will have a mean of ‘0.08’

Question 13

How to interpret the S/D of DIFF IN PROP

Answer 13

For all random samples of ‘50 students’ from ‘high school A’ and ‘50 students’ from ‘high school B’, the difference (‘A-B’) in sample proportions of ‘students who have a driver’s license’ typically vary by about ‘0.087’ from the true difference of ‘0.08’

Question 14

How to interpret the probability of diff in prop

Answer 14

Getting a diff (A-B) in sample proportions of ‘0 or less/more happens about x% of all possible samples of size 50 from these populations.

Question 15

How to interpret the MEAN sample dist of MEAN

Answer 15

For all random samples of size n = x from this population, the sample mean ‘weights of lemons’ will have a mean of ‘y units’

Question 16

How to interpret the S/D sample dist of MEAN

Answer 16

For all random samples of size n = x from this population, the sample mean ‘weights of lemons’ will typically vary by about ‘s/d’ units from the population mean of ‘’

Question 17

how to interpret the MEAN of sampling dist of DIFF IN MEANS

Answer 17

For all random samples of 6 lemons from the
lemon tree and 6 oranges from the orange tree,
the differences (L - O) in sample mean weight
will have a mean of 1 ounce.

Question 18

how to interpret the SD of sampling dist of DIFF IN MEANS

Answer 18

For all random samples of 6 lemons from the
lemon tree and 6 oranges from the orange tree,
the differences (L - O) in sample mean weight
will typically vary by about 0.26 ounces from the
true difference in means of 1 ounce.