one sample
This test is used to determine if a sample mean is significantly different from a population mean when the population standard deviation is unknown.
What is a one-sample t-test?
This test compares the means of two independent groups when population standard deviations are unknown.
What is a two-sample t-test?
This test is used when the population standard deviation is known.
What is a one-sample z-test?
This test compares two population means when both population standard deviations are known.
What is a two-sample z-test?
In a one-sample t-test, identify what each of these represents:
xˉ,μ,s,n
In a two sample t-test, what do these represent:
x1,x2,s1,s2
x1, x2: Sample means
s1, s2: Sample standard deviations
Identify the following variables:
xˉ,μ,σ,n
What do these represent:
μ1, μ2, σ1, σ2
μ1,μ2: population means
σ1,σ2: population standard deviations
Given: x=50,μ=45,s=10,n=25, plug into the test statistic formula.
(opinon)
x1 = 80, s1 = 10, n1 = 25
x2 = 70, s2 = 8, n2 = 25
xˉ=200, μ=180, σ=40, n=16
z = 200-180/40/4 = 20/10 = 2
xˉ1=60, xˉ2 = 55, σ1=10, σ2=10, n1=n2=25
z = 5/(squareroot 4+4) = 5/(squareroot 8) = 1.77
A company claims their energy drink gives an average boost of 100 mg of caffeine effect. A sample of 30 drinks has a mean of 110 and s=20s = 20s=20. Test the claim.
ho: = 100
ha: = 100
Test statstic test: 2.74
Compare ticket prices:
Online: mean = 120, s = 25, n = 40
Box Office: mean = 100, s = 20, n = 35
Ho: u1 = u2
Ha: u1 does not equal u2
Average sleep is claimed to be 8 hours. A sample of 50 students has a mean of 7.5 hours, σ=1.
z = 7.5 - 8/1(squarerooted)50 = -3.54
Airline A delay: mean = 30 min
Airline B delay: mean = 20 min
σ=10, sample sizes = 50 each
30-20/(square root 100/50+100/50) = 10/ (square root 2+2) = 10/2 = 5
Strong evidence Airline A has longer delays.