Biology Homework Stansard Deviation
Biology Homework #1
1 An error bar drawn on a graph or chart must always be a representation of:
-Variation shown by the data
2 The width of 10 leaves was measured and the values in mm were 12, 13, 13, 14, 14, 14, 14, 15, 15, 16. The mean is 14.0mm.What is the best estimate of the standard deviation?
-1mm
5 1000 bananas were collected from a single plantation and weighed.Their masses formed a normal distribution. How many bananas would be expected to be within 2 standard deviations of the mean?
-950
6 In a normal distribution, what percentage of values fall within ±1 standard deviation of the mean and ±2 standard deviations of the mean?
-1= 68%
-2=95%
7 The lengths of the leaves of dandelion plants growing on a lawn were measured.The mean length was 35mm and the standard deviation was 4mm.A second set of data on dandelion leaf length was collected from a wasteland area some distance away.The mean was 97mm and the standard deviation 20mm.What can you say about the differences in the lengths of the dandelion leaves from the two different habitats?
-The leaves growing on the lawn have a smaller standard deviation than the ones growing on the wasteland. The graph of the lawn dandelions would have a tall and narrow variation curve while the other one would have a flatter and wider curve. Also the error bars on the dandelions growing on the wasteland would be bigger in length than the ones on the lawn.
8 Salmon live and reproduce in two rivers in Norway – the Namsen and Gaula rivers. Data were collected on the number of eggs laid by the salmon in these two rivers. In the River Namsen, the mean number laid was 1200 eggs per salmon and the standard deviation was 45. For the River Gaula, the mean was 770 eggs per salmon and the standard deviation was 48. Is there a difference between the number of eggs laid by the fish in the two different rivers?
-Yes, the salmon living in the Namsen river lays on average 430 more eggs than the ones that live in the Gaula
1 An error bar drawn on a graph or chart must always be a representation of:
-Variation shown by the data
2 The width of 10 leaves was measured and the values in mm were 12, 13, 13, 14, 14, 14, 14, 15, 15, 16. The mean is 14.0mm.What is the best estimate of the standard deviation?
-1mm
5 1000 bananas were collected from a single plantation and weighed.Their masses formed a normal distribution. How many bananas would be expected to be within 2 standard deviations of the mean?
-950
6 In a normal distribution, what percentage of values fall within ±1 standard deviation of the mean and ±2 standard deviations of the mean?
-1= 68%
-2=95%
7 The lengths of the leaves of dandelion plants growing on a lawn were measured.The mean length was 35mm and the standard deviation was 4mm.A second set of data on dandelion leaf length was collected from a wasteland area some distance away.The mean was 97mm and the standard deviation 20mm.What can you say about the differences in the lengths of the dandelion leaves from the two different habitats?
-The leaves growing on the lawn have a smaller standard deviation than the ones growing on the wasteland. The graph of the lawn dandelions would have a tall and narrow variation curve while the other one would have a flatter and wider curve. Also the error bars on the dandelions growing on the wasteland would be bigger in length than the ones on the lawn.
8 Salmon live and reproduce in two rivers in Norway – the Namsen and Gaula rivers. Data were collected on the number of eggs laid by the salmon in these two rivers. In the River Namsen, the mean number laid was 1200 eggs per salmon and the standard deviation was 45. For the River Gaula, the mean was 770 eggs per salmon and the standard deviation was 48. Is there a difference between the number of eggs laid by the fish in the two different rivers?
-Yes, the salmon living in the Namsen river lays on average 430 more eggs than the ones that live in the Gaula