Normal Distribution

Statistics

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13. In a dog obedience class, the masses of the 60 dogs enrolled were normally distributed, with a mean of 11.2 kg and a standard deviation of 2.8 kg. How many dogs would you expect to fall within each range of masses? a) between 8.4 kg and 14.0 kg b) between 5.6 kg and 16.8 kg c) between 2.8 kg and 19.6 kg d) less than 11.2 kg1. The ages of members of a seniors curling club are normally distributed, with a mean of 63 years and a standard deviation of 4 years. What percent of the curlers is in each of the following age groups? a) between 55 and 63 years old b) between 67 and 75 years old c) older than 75 years old 2. A teacher is analyzing the class results for three biology tests. Standard Each set of marks is normally distributed. Test Mean (p) Deviation (or) a) Sketch normal curves for tests 1 and 2 on one graph. 1 77 3.9 Sketch normal curves for tests I and 3 on a different 2 83 3.9 graph. 3 77 7.4 b) Examine your graphs. How do tests 1 and 3 compare? How do tests I and 2 compare? c) Determine Oliver's marks on each test, given the information Oliver's shown at the right.an A school of 130 bottlenose dolphins is living in a protected environment The life expectancy of the dolphins is normally distributed, with a mean of 39 years and a standard deviation of 3.5 years. How many of these dolphins can be expected to live more than 46 years? 11. Julie is an engineer who designs roller coasters. She wants to design a roller coaster that 95% of the population can ride. The average adult in North America has a mass of 71.8 kg, with a standard deviation of 13.6 kg. a) What range of masses should Julie consider in her design? b) If Julie wanted to design a roller coaster that 99.7% of the population could ride, what range of masses should she consider? c) What assumption is being made, which could cause problems if it is not valid