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In a survey, 14 people were asked how much they spent on their child's last birthday gift. The resultswere roughly bell-shaped with a mean of $39 and a standard deviation of $5. Construct a confidenceinterval at a 95% confidence level.Give your answers to one decimal place.

In a survey 14 people were asked how much they spent on their childs last birthday gift The resultswere roughly bellshaped with a mean of 39 and a standard devi class=

Respuesta :

SOLUTION:

[tex]C.I=\bar{\text{ }x}\pm t\frac{s}{\sqrt{n}}[/tex]

Inserting the values;

[tex]\begin{gathered} \bar{x}=39 \\ s=5 \\ n=14 \\ t_{0.95}=2.16 \end{gathered}[/tex][tex]\begin{gathered} C.I=39\pm\frac{2.16\times5}{\sqrt{14}} \\ \\ \end{gathered}[/tex]

Thus, the confidence interval is;

[tex](36.4\text{ }to\text{ }41.6)[/tex]

or

[tex]39\pm2.6[/tex]

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