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2.5 Statistical Hypothesis Testing

2.5 Statistical Hypothesis Testing

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Question 4

The battery life, in hours, for a fully charged wireless keyboard is normally distributed with mean 50 hours and standard deviation 6 hours. Hannah has a fully charged wireless keyboard.

a.

Find the probability that the keyboard lasts longer than 45 hours.

[1]
b.

Hannah uses her keyboard for 45 hours. Find the probability that Hannah's keyboard lasts for another 10 hours.

[4]
c.

Hannah believes that the mean battery life of the wireless keyboards are longer than 50 hours. She took a random sample of 20 of these keyboards and found that their mean lifetime was 51.1 hours. Stating your hypotheses clearly and using a 5% level of significance, test Hannah's belief.

[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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