1. Statistical Analysis

3. Make effective conclusions

7. This variation can be shown using a frequency distribution graph

8. The mean value is in the middle of the distribution

10. 95% of the data is within 2 SD from the mean

14. 68% of data is +/- 1SD, so 68% are between 2.0cm and 3.0cm

16. Starter In a population of men the systolic blood pressure shows a normal distribution. The mean of the population is 125 (measured in mm and Hg) and the standard deviation is 10. If the population was 1000, how many of them have a blood pressure between 115 and 135mm Hg? 680 men have blood pressure between 115 and 135mm Hg. If the mean is 125, and the standard deviation is 10, then +1 Sx is 135, and -1 Sx is 115, and we know that 68% of your data (in this case the men) are +/-1 Sx from the mean.

18. Find the mean of your data

20. Insert Graph (Scatter)

23. Means A = 10 B = 20

24. Means A = 10 B = 20 Is there a significant difference between the means?

25. Means A = 10 B = 20 Is there a significant difference between the means?

26. Means A = 10 B = 20 Is there a significant difference between the means? Would knowing the standard deviations help? What if both had “large” standard deviations?

27. Means A = 10 B = 20 Is there a significant difference between the means? Would knowing the standard deviations help? What if both had “small” standard deviations?

28. Means A = 10 B = 20 Is there a significant difference between the means? Would knowing the population size help? What if one had a large population size and the other a small size? What if both were large or both small?

29. The t-test takes from both samples: the means, the standard deviations and the population size into account and will give you a t-value which you can use with a t-test table to determine if there is a statistically significant difference between the means. DO NOT learn the formula. The t-value will be given to you.

31. α significance level

32. Calculated Value of t > critical value it has is <0.05 which means there is a significant difference

34. H0 Null Hypothesis states that there is no significant difference between the two groups Never want to assume there is a difference The null hypothesis typically corresponds to a general or default position. For example, the null hypothesis might be that there is no relationship between two measured phenomena or that a potential treatment has no effect.