Exam 2 Flashcards
1
Q
Simple Random Sample
A
- A sample selected as such so that each possible sample size has the same probability of being selected
2
Q
Sampling Distribution of the sample mean
A
- Is the probability distribution of all possible values of the sample mean
3
Q
Expected Value of the Sample mean
A
- This equals the population mean, if the sample mean is unbiased
4
Q
Standard deviation of the Sample mean
A
- This equals the Standard Error of the Sample Mean
5
Q
Degrees of Freedom
A
- Equals n-1
- As the degrees of freedom increases, the t-distribution looks more like a standard normal distribution
6
Q
Hypothesis Test
A
- To determine whether a statement about the value of the population parameter should or should not be rejected
7
Q
Ho
A
- A tentative assumption about the population called the null hypothesis
- Ho and Ha can’t both be true
8
Q
Ha
A
- Alternative Hypothesis, opposite of null hypothesis
9
Q
Rejecting Ho
A
- Getting enough evidence saying Ha is true
10
Q
Not Rejecting Ho
A
- Not getting enough evidence to support Ha
11
Q
Type 1 Error
A
- A Type I error occurs when Ho is true in reality, but we reject Ho in our hypothesis test.
12
Q
Type 2 Error
A
- A Type II error occurs when Ha is true but we do not reject Ho.
- Probability of creating type 2 errors is difficult to be determined
13
Q
Level of Significance
A
- The probability of making a Type I error when Ho is true as an equality
- Denoted by Greek letter alpha (a)
14
Q
Test Statistic
A
- Is a measure of how far the sample mean x is from
the hypothesized value µo. - The bigger the test statistic, the farther away the sample mean is from the population mean
- The bigger the test statistic, the more evidence we have that the null hypothesis is not true
15
Q
p-values
A
- Allows us to say that we have strong, moderate, or no evidence that Ho is false
- Is a probability that provides a measure of the evidence that prevents the null hypothesis
- The smaller the p-value the more evidence against Ho
16
Q
p-value Lower tail test
A
- The area under the standard normal curve to the LEFT of the test statistic.
17
Q
p-value Upper tail test
A
- The area under the standard normal curve to the RIGHT of the test statistic.
18
Q
Two-Tailed Test
A
- If the value of the test statistic is negative, the p-value is the area under the standard normal curve to the LEFT of the test statistic multiplied by 2.
- If the value of the test statistic is positive, the p-value is the area under the standard normal curve to the RIGHT of the test statistic multiplied by 2.
