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Understanding Statistical
inference
Inference
• The process of drawing conclusions about population parameters
based on a sample taken from the population
Key points when you draw an inference
1)A sample is likely to be a good representation of
the population
2)There is an ele...
t test
T tests
1.One Sample t test
2.Independent Samples t test
3.Dependent Samples t test
What is hypotheses?
•In statistics, a hypothesis is a claim or statement
about a property of a population
State alpha
• α = 0.05
3. Calculating the degree of freedom
• n-1 = 30-1 = 29
In statistics, the number of degrees of freedom is the number of va...
4. State the decision rule
If t is less than -2.0452 and greater than 2.0452 reject the null hypothesis.
Reject Null Hypothesis
Independent samples t test
Pooled Variance
Sum of Squares
Variance
• What Is the Sum of Squares?
• Sum of squares is a statistical technique used in statistical analysis to
determine the di...
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
Inferential Statistics
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Inferential Statistics

Understanding t-tests and inferential statistics

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Inferential Statistics

  1. 1. Understanding Statistical inference
  2. 2. Inference • The process of drawing conclusions about population parameters based on a sample taken from the population
  3. 3. Key points when you draw an inference 1)A sample is likely to be a good representation of the population 2)There is an element of uncertainty as to how well the sample represents the population. 3)The way the sample is taken matters.
  4. 4. t test
  5. 5. T tests 1.One Sample t test 2.Independent Samples t test 3.Dependent Samples t test
  6. 6. What is hypotheses? •In statistics, a hypothesis is a claim or statement about a property of a population
  7. 7. State alpha • α = 0.05
  8. 8. 3. Calculating the degree of freedom • n-1 = 30-1 = 29 In statistics, the number of degrees of freedom is the number of values in the final calculation of a statistic that are free to vary. The number of independent ways by which a dynamic system can move, without violating any constraint imposed on it, is called number of degrees of freedom.
  9. 9. 4. State the decision rule
  10. 10. If t is less than -2.0452 and greater than 2.0452 reject the null hypothesis.
  11. 11. Reject Null Hypothesis
  12. 12. Independent samples t test
  13. 13. Pooled Variance Sum of Squares Variance
  14. 14. • What Is the Sum of Squares? • Sum of squares is a statistical technique used in statistical analysis to determine the dispersion of data points. • What is pooled variance? • In statistics, pooled variance (also known as combined, composite, or overall variance) is a method for estimating variance of several different populations when the mean of each population may be different, but one may assume that the variance of each population is the same.

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