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Bar Chart Data Analysis First Generation Third Generation.

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Presentation on theme: "Bar Chart Data Analysis First Generation Third Generation."— Presentation transcript:

1 Bar Chart Data Analysis First Generation Third Generation

2 Do English ivy leaves grown in the shade have a larger surface area than English ivy leaves grown in the sun?

3 It is evident from the graph that the error bars for the shady leaf mean do not overlap with the error bars for the sunny leaf mean. In fact, had the researchers chosen to plot ±2SE error bars, they, too, would not have overlapped. This non-overlap strongly suggests that there is a high probability that the two populations are indeed different from each other.

4 Parametric Data The underlying source population is normally distributed. We are going to assume that we are dealing with parametric data.

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6 Standard Deviation The standard deviation a way to measure how close together the elements are in a set of data. The standard deviation is the average distance between each data point and the mean. X = each value = mean N = number of values

7 A little more that two-thirds of the data points fall between +1 standard deviation and -1 standard deviation from the sample mean. More than 95% of the data falls between ±2 standard deviations from the sample mean.

8 Standard Error A statistic that allows you to make an inference about how well the sample mean matches up to the true population mean. A sample mean of ±1 SE describes the range of values about which an investigator can have approximately 67% confidence that the range includes the true population mean. A sample with a ±2 SE defines a range of values with approximately a 95% certainty.

9 A sample mean of ±1 SE describes the range of values about which an investigator can have approximately 67% confidence that the range includes the true population mean. A sample with a ±2 SE defines a range of values with approximately a 95% certainty.

10 It is evident from the graph that the error bars for the shady leaf mean do not overlap with the error bars for the sunny leaf mean. In fact, had the researchers chosen to plot ±2SE error bars, they, too, would not have overlapped. This non-overlap strongly suggests that there is a high probability that the two populations are indeed different from each other.

11 A sample mean of ±1 SE describes the range of values about which an investigator can have approximately 67% confidence that the range includes the true population mean. A sample with a ±2 SE defines a range of values with approximately a 95% certainty.

12 Standard Deviation The standard deviation a way to measure how close together the elements are in a set of data. The standard deviation is the average distance between each data point and the mean. X = each value = mean N = number of values

13 Mean The arithmetic mean or average of a set of numbers is the expected value. The mean is calculated by adding up all the values, and then dividing that sum by the number of values. Median The median is the middle value in a set of values. To find the median, order the numbers from largest to smallest, and then choose the value in the middle. If you have a data set with an even number of values take the average of the two middle numbers.

14 Mode The mode of a set is the value or values that occur most frequently. There can be more than one mode in a set. If there is more than one mode, you simply list all of the modes. Range The range of a set of numbers is the maximum distance between any two values. In other words, it's the difference between the largest and smallest values.


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