It is advertised that the average braking distance for a small car traveling at 75 miles per hour equals 120 feet. A transportation researcher wants to determine if the statement made in the advertisement is false. She randomly test drives 36 small cars at 75 miles per hour and records the braking distance. The sample average braking distance is computed as 115 feet. Assume that the population standard deviation is 23 feet. (You may find it useful to reference the appropriate table: z table or t table) a. State the null and the alternative hypotheses for the test. multiple choice 1 H0: μ = 120; HA: μ ≠ 120 H0: μ ≥ 120; HA: μ < 120 H0: μ ≤ 120; HA: μ > 120 b-1. Calculate the value of the test statistic. (Negative value should be indicated by a minus sign. Round intermediate calculations to at least 4 decimal places and final answer to 2 decimal places.) b-2. Find the p-value. multiple choice 2 p-value < 0.01 0.01 p-value < 0.025 0.025 p-value < 0.05 0.05 p-value < 0.10 p-value 0.10 c. Use α = 0.05 to determine if the average breaking distance differs from 120 feet.
It is advertised that the average braking distance for a small car traveling at 75 miles per hour equals 120 feet. A transportation researcher wants to determine if the statement made in the advertisement is false. She randomly test drives 36 small cars at 75 miles per hour and records the braking distance. The sample average braking distance is computed as 115 feet. Assume that the population standard deviation is 23 feet. (You may find it useful to reference the appropriate table: z table or t table)
a. State the null and the alternative hypotheses for the test.
multiple choice 1
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H0: μ = 120; HA: μ ≠ 120
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H0: μ ≥ 120; HA: μ < 120
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H0: μ ≤ 120; HA: μ > 120
b-1. Calculate the value of the test statistic. (Negative value should be indicated by a minus sign. Round intermediate calculations to at least 4 decimal places and final answer to 2 decimal places.)
b-2. Find the p-value.
multiple choice 2
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p-value < 0.01
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0.01p-value < 0.025
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0.025p-value < 0.05
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0.05p-value < 0.10
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p-value0.10
c. Use α = 0.05 to determine if the average breaking distance differs from 120 feet.
Given ,
Sample size = n = 36
Sample mean = = 115 feet
Population standard deviation = = 23 feet
Claim : the average braking distance for a small car traveling at 75 miles per hour equals 120 feet
In statistical notation , = 120
So hypothesis is ,
HA : ≠ 120
Two tailed test.
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