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A survey was carried out on behalf of a television station to investigate the popularity of a certain show - Leaving Cert Mathematics - Question b - 2018

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A survey was carried out on behalf of a television station to investigate the popularity of a certain show. (i) A random sample of 1560 television viewers was surve... show full transcript

Worked Solution & Example Answer:A survey was carried out on behalf of a television station to investigate the popularity of a certain show - Leaving Cert Mathematics - Question b - 2018

Step 1

A random sample of 1560 television viewers was surveyed. Find the margin of error of the survey. Give your answer as a percentage, correct to 1 decimal place.

96%

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Answer

To find the margin of error (MOE) for the survey, we use the formula:

MOE = rac{1}{ ext{squared root of } n}

where nn is the sample size. In this case, n=1560n = 1560.

Substituting the values, we have: MOE = rac{1}{ ext{squared root of } 1560} \approx 0.025318

To express this as a percentage:

MOE=0.025318×1002.5%MOE = 0.025318 \times 100 \approx 2.5\%.

Thus, the margin of error is 2.5%.

Step 2

In the survey, 546 of the 1560 viewers surveyed said that they liked the show. Use your answer to part b(i) above to create a 95% confidence interval for the percentage of viewers who liked the show.

99%

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Answer

To find the 95% confidence interval for the percentage of viewers who liked the show, we can use the formula:

CI=[p^MOE,p^+MOE]CI = \left[ \hat{p} - MOE, \hat{p} + MOE \right]

where:

  • p^=5461560=0.35\hat{p} = \frac{546}{1560} = 0.35 (proportion of viewers who liked the show)
  • MOE=0.025318MOE = 0.025318 (from part b(i)).

Thus, the confidence interval becomes: CI=[0.350.025318,0.35+0.025318][0.3247,0.3753]CI = \left[ 0.35 - 0.025318, 0.35 + 0.025318 \right] \approx [ 0.3247, 0.3753 ]

Converting these proportions to percentages: CI=[32.5%,37.5%]CI = [32.5\%, 37.5\%]

The 95% confidence interval for the percentage of viewers who liked the show is approximately [32.5%, 37.5%].

Step 3

An executive for the television station had claimed that 40% of viewers liked the show. Use your answer to part b(ii) above to conduct a hypothesis test, at the 5% level of significance, to test the executive's claim. State your null hypothesis, your alternative hypothesis and give your conclusion in the context of the question.

96%

101 rated

Answer

To conduct a hypothesis test to evaluate the executive's claim, we state:

  • Null Hypothesis (H₀): p=0.40p = 0.40 (40% of viewers liked the show)
  • Alternative Hypothesis (H₁): p0.40p \neq 0.40 (the proportion of viewers who liked the show is not 40%)

Using our confidence interval from part b(ii), which is approximately [32.5%, 37.5%], we can conclude:

Since the claimed proportion of 40% is not included within the confidence interval, we reject the null hypothesis (H₀). There is insufficient evidence to support the executive's claim that 40% of viewers liked the show.

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