Question

Complete the tasks and answer the questions. Use the 2SD method to estimate the true proportion of the population of your city that dislikes the taste of cilantro. State the resulting confidence interval in both forms – the interval notation and the sample proportion ± the margin of error notation. Write the interpretation of this confidence interval. Use the theory-based method to estimate the true proportion of the population of your city that dislikes the taste of cilantro with a 95% confidence interval. State the resulting confidence interval in both forms – the interval notation and the sample proportion ± the margin of error notation. Write the interpretation of this confidence interval. Use the theory-based method to estimate the true proportion of the population of your city that dislikes the taste of cilantro with an 88% confidence interval. State the resulting confidence interval in both forms – the interval notation and the sample proportion ± the margin of error notation. Write the interpretation of this confidence interval. Your initial post should be made before the end of the fourth day (Saturday) of the module to receive full credit. Return at least once later in the module to comment on at least one classmate's posts. Do NOT "post and run" – making all of your posts on the same visit. You need multiple visits to the Discussions to gain multiple perspectives by reading all of the posts and replies.

Answer 1

Complete Question

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Answer:

Using 2SD Method

The confidence interval is

     The interval notation :  $(0.108 , 0.212 )$

     The interval notation and the sample proportion ± the margin of error

     notation:$0.16 \pm 0.052$

 The  interpretation

    There is  95% confidence that the true proportion of those that dislike  cilantro lie within the upper(0.212) and the lower(0.108) limit of the calculate confidence interval

Using theory-based method      

      The 95% confidence interval is

            The interval notation :   $(0.109 , 0.211 )$

     The interval notation and the sample proportion ± the margin of error

     notation:$0.16 \pm 0.051$

 The  interpretation

      There is  95% confidence that the true proportion of those that dislike  cilantro lie within the upper(0.211) and the lower(0.109) limit of the calculate confidence interval

Using theory-based method  

 The 88% confidence interval is  

         The interval notation :   $(0.120 , 0.200 )$

          The interval notation and the sample proportion ± the margin of

           error notation:   $0.16 \pm 0.040$

The interpretation is

  There is  88% confidence that the true proportion of those that dislike  cilantro lie within the upper(0.200 ) and the lower(0.120) limit of the calculate confidence interval.

Step-by-step explanation:

From the question we are told that

The number sample size is n = 200

The number of people that dislike cilantro is k = 32

Generally the sample proportion is mathematically represented as

$\r p = \frac{k}{N}$

=> $\r p = \frac{32}{200}$

=> $\r p = 0.16$

Generally 2SD confidence interval is mathematically represented as

$\r p \pm 2\sqrt{\frac{\r p(1 - \r p)}{n} }$

substituting value

$0.16 \pm 2\sqrt{\frac{0.16(1 - 0.16)}{200} }$

=> $0.16 \pm 0.052$

This can also be represented as

$(0.16 - 0.052 , 0.06 + 0.052)$

=> $(0.108 , 0.212 )$

Generally this confidence interval can be interpreted as

There is 95% confidence that the true proportion of those that dislike cilantro lie within the upper and the lower limit of the calculate confidence interval

Using theory-based method estimate 95% confidence interval

Generally from the question the confidence level is 95% hence the level of significance is calculated as

$\alpha = (100 - 95)\%$

=> $\alpha = 0.05$

The critical value of $\frac{\alpha }{2}$ from the normal distribution table is

$Z_{\frac{\alpha }{2} } = 1.96$

Generally the confidence level using theory base method is

$0.16 \pm 1.96 \sqrt{\frac{0.16 (1- 0.16)}{200} }$

=>     $0.16 \pm 0.051$

This can also be represented as

$(0.16 - 0.051 , 0.06 + 0.051)$

=> $(0.109 , 0.211 )$

Generally this confidence interval can be interpreted as

There is 95% confidence that the true proportion of those that dislike cilantro lie within the upper(0.211) and the lower(0.109) limit of the calculate confidence interval

Using theory-based method estimate 88% confidence interval

Generally from the question the confidence level is 95% hence the level of significance is calculated as

$\alpha = (100 - 88)\%$

=> $\alpha = 0.12$

The critical value of $\frac{\alpha }{2}$ from the normal distribution table is

$Z_{\frac{\alpha }{2} } =Z_{\frac{0.12 }{2} } = 1.55$

Generally the confidence level using theory base method is

$0.16 \pm 1.55 \sqrt{\frac{0.16 (1- 0.16)}{200} }$

=>     $0.16 \pm 0.040$

This can also be represented as

$(0.16 - 0.040 , 0.06 + 0.040)$

=> $(0.120 , 0.200 )$

Generally this confidence interval can be interpreted as

There is 88% confidence that the true proportion of those that dislike cilantro lie within the upper(0.200 ) and the lower(0.120) limit of the calculate confidence interval