1. Topic One: IB Biology The science of data

15. These two averages should be close to the same

18. Average value Value farthest from average Calculated distance

22. How can leaf lengths be displayed graphically?

23. Simply measure the lengths of each and plot how many are of each length

24. If smoothed, the histogram data assumes this shape

27. A typical standard distribution curve

35. Here is an example

36. Comparison of Two Samples Two of the same type of Mollusks from two different locations

38. Standard deviation in the error bar

41. Comparison of Two Samples Using a t-Test

42. t -test The t -test compares the averages and standard deviations of two samples to see if there is a significant difference between them. We start by calculating a number , t t can be calculated using the equation: ( x 1 – x 2 ) (s 1 ) 2 n 1 (s 2 ) 2 n 2 + t = Where: x 1 is the mean of sample 1 s 1 is the standard deviation of sample 1 n 1 is the number of individuals in sample 1 x 2 is the mean of sample 2 s 2 is the standard deviation of sample 2 n 2 is the number of individuals in sample 2

43. This is done on a calculator or in excel

47. In fx in Category pick Statistical and then find t test in select function

53. You now have a t test value

55. .03% is less then .05%

58. Negative 1 correlation

60. A correlation coefficient of 0 means that the two variables, age and height, are unrelated to one another

61. Correlation Coefficient +1.00

63. Creating a Scatter graph in Excel

65. Highlight your Numbers and Selected Chart Wizard

66. In Chart Wizard chose Scatter graph

67. Label your graph & x and y axis

68. To added a trendline RIGHT click on any data point

69. Choice linear

70. You can now clip and paste it into word for you lab