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4.5 Statistical distributions (A-level only)

4.5 Statistical distributions (A-level only)

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Question 23

A brand of LED lightbulbs claims to have a mean lifespan of 1200 hours.

An electrical engineer believes that the actual mean lifespan is less than 1200 hours.

The engineer tests a large batch of bulbs and produces the following summary data:

n=300∑x=357900∑x2=427454700 n = 300 \quad \sum x = 357900 \quad \sum x^2 = 427454700 n=300∑x=357900∑x2=427454700
a.

Find the mean and standard deviation of the sample.

[3]
b.

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

[5]
Markscheme

4.5 Statistical distributions (A-level only) Questions

  1. A Level
  2. /Maths
  3. /4.5 Statistical distributions (A-level only)

284 exam-style questions on CCEA A Level Maths 4.5 Statistical distributions (A-level only), covering 4.5.1 Statistical distributions (A-level only) and 4.5.2 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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