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2.5 Statistical Hypothesis Testing

2.5 Statistical Hypothesis Testing

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Question 28

A safety engineer tests the breaking strength of steel cables. The manufacturer claims the cables have a mean breaking strength of 80 kN. The engineer suspects the cables are weaker than claimed. Data from 200 cables are summarized below:

n=200∑x=15940∑x2=1271162 n = 200 \quad \sum x = 15940 \quad \sum x^2 = 1271162 n=200∑x=15940∑x2=1271162
a.

Find the mean and standard deviation of the sample.

[3]
b.

Carry out a hypothesis test to test the engineer's suspicion at the 1% significance level. State your assumptions clearly.

[5]
Markscheme

2.5 Statistical Hypothesis Testing Questions

  1. A Level
  2. /Maths
  3. /2.5 Statistical Hypothesis Testing

316 exam-style questions on OCR A Level Maths 2.5 Statistical Hypothesis Testing, covering 2.5.1 The language of hypothesis testing, 2.5.2 Hypothesis test for a binomial proportion, 2.5.3 Inference and significance level, 2.5.4 Sample mean as a random variable (A-level only), 2.5.5 Hypothesis test for the mean of a normal distribution (A-level only), 2.5.6 Pearson's product-moment correlation coefficient, and 2.5.7 Hypothesis test using Pearson's coefficient (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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