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2.4.8 Normal distribution as a model (A-level only)

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Question 6

The random variable $X$ is normally distributed with unknown mean $μ\mu$ and known variance $σ2\sigma^2$ . A random sample of $n$ observations of $X$ produced a $95%95\%$ confidence interval for $μ\mu$ of $(12.42, 12.85)$ .

Show that the standard error used to find this confidence interval is $0.110$ to $3$ significant figures.

[3]

Using the same random sample,

find a $98%98\%$ confidence interval for $μ\mu$ . Give your answers to $3$ decimal places.

[4]

The $r%r\%$ confidence interval using the same random sample has a width of $0.50$ .

Calculate the value of $r$ .

[4]

Markscheme

2.4.8 Normal distribution as a model (A-level only) Questions

A Level
Maths
2.4.8 Normal distribution as a model (A-level only)

79 exam-style questions on OCR (MEI) A Level Maths 2.4.8 Normal distribution as a model (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

2.4.8 Normal distribution as a model (A-level only)

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2.4.8 Normal distribution as a model (A-level only)

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Question 6

Show that the standard error used to find this confidence interval is $0.110$ to $3$ significant figures.

[3]

Using the same random sample,

find a $98%98\%$ confidence interval for $μ\mu$ . Give your answers to $3$ decimal places.

[4]

The $r%r\%$ confidence interval using the same random sample has a width of $0.50$ .

Calculate the value of $r$ .

[4]

Markscheme

2.4.8 Normal distribution as a model (A-level only) Questions

A Level
Maths
2.4.8 Normal distribution as a model (A-level only)

79 exam-style questions on OCR (MEI) A Level Maths 2.4.8 Normal distribution as a model (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.