Question

The mean height for an 8th grader in the State of Florida is 146 cm with a standard deviation of 8 cm. Given a normal distribution, use the Empirical Rule to interpret the data. What percent of 8th graders heights are between 138 cm and 162 cm? What percent of 8th graders heights are between 122 cm and 170 cm? What percent of 8th graders heights are between 130 cm and 162 cm?

Answer 1

Answer:

a) 68%

b) 99.7%

c) 95%

Step-by-step explanation:

The mean height for an 8th grader in the State of Florida is 146 cm with a standard deviation of 8 cm. Given a normal distribution, use the Empirical Rule to interpret the data.

Empirical rule states that:

68% of data falls within 2 standard deviations from the mean - between μ – σ and μ + σ .

95% of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ .

99.7% of data falls within 3 standard deviations from the mean - between μ - 3σ and μ + 3σ .

Mean = 146

Standard deviation = 8cm

a) What percent of 8th graders heights are between 138 cm and 162 cm?

146 - sx = 138cm

146 - 138 cm = 8cm

146 - 162 cm = 8cm

Hence,68% of data falls within 2 standard deviations from the mean - between μ – σ and μ + σ .

b) What percent of 8th graders heights are between 122 cm and 170 cm?

Standard deviation = 8

146 - 122 = 24 cm

146 - 170 = -24cm

24cm/8 cm = 3

Hence,99.7% of data falls within 3 standard deviations from the mean - between μ - 3σ and μ + 3σ .

c) What percent of 8th graders heights are between 130 cm and 162 cm?

146 cm - 130cm = 16cm

162 cm - 146 cm = 16 cm

16cm/8cm

= 2

Hence, 95% of data falls within 2 standard deviations from the mean - between μ – 2σ and μ + 2σ .