Step 1

Given information:

\(\displaystyle{n}={54}\)

\(\displaystyle\hat{{{p}}}={0.124}\)

\(\displaystyle{x}={54}\times{0.124}\)

Confidence level \(\displaystyle={80}\%\)

Step 2

The step by step procedure to determine confidence interval for proportion:

1) Press STAT and scroll right to the TESTS menu.

2) Scroll down to A:1-PropZInt and press ENTER.

3) Enter the values, \(\displaystyle{x}={6.696},\ {n}={54}\) and C-Level \(\displaystyle={0.80}.\)

4) Select Calculate and press ENTER. NKS Step 3

The obtained \(\displaystyle{80}\%\) confidence interval for the population proportion, p is \(\displaystyle{\left({0.0665},\ {0.1815}\right)}\).

Yes the proportion of left handed in U.S i.e \(\displaystyle{13.1}\%\) falls in our confidence interval \(\displaystyle{\left({0.0665},\ {0.1815}\right)}\).

Given information:

\(\displaystyle{n}={54}\)

\(\displaystyle\hat{{{p}}}={0.124}\)

\(\displaystyle{x}={54}\times{0.124}\)

Confidence level \(\displaystyle={80}\%\)

Step 2

The step by step procedure to determine confidence interval for proportion:

1) Press STAT and scroll right to the TESTS menu.

2) Scroll down to A:1-PropZInt and press ENTER.

3) Enter the values, \(\displaystyle{x}={6.696},\ {n}={54}\) and C-Level \(\displaystyle={0.80}.\)

4) Select Calculate and press ENTER. NKS Step 3

The obtained \(\displaystyle{80}\%\) confidence interval for the population proportion, p is \(\displaystyle{\left({0.0665},\ {0.1815}\right)}\).

Yes the proportion of left handed in U.S i.e \(\displaystyle{13.1}\%\) falls in our confidence interval \(\displaystyle{\left({0.0665},\ {0.1815}\right)}\).