Suppose you are investigating the relationship between two variables, traffic flow and expected lead content, where traffic flow is a predictor of lead content. You find the 95% CI for expected lead content when traffic flow is 15, based on a sample of n= 10 observations, is (461.7, 598.1).

Required:
What parameter is this interval estimating?

Respuesta :

Answer:

The answers is " Option B".

Step-by-step explanation:

[tex]CI=\hat{Y}\pm t_{Critical}\times S_{e}[/tex]

Where,

[tex]\hat{Y}=[/tex] predicted value of lead content when traffic flow is 15.

[tex]\to df=n-1=8-1=7[/tex]

 [tex]95\% \ CI\ is\ (463.5, 596.3) \\\\\hat{Y}=\frac{(463.5+596.3)}{2}\\\\[/tex]

     [tex]=\frac{1059.8}{2}\\\\=529.9[/tex]

Calculating thet-critical value[tex]t_{ \{\frac{\alpha}{2},\ df \}}=-2.365[/tex]

The lower predicted value [tex]=529.9-2.365(Se)[/tex]

[tex]463.5=529.9-2.365(Se)\\\\529.9-463.5=2.365(Se)\\\\66.4=2.365(Se)\\\\Se=\frac{66.4}{2.365} \\\\Se=28.076[/tex]

When [tex]99\%[/tex] of CI use as the expected lead content: [tex]\to 529.9\pm t_{0.005,7}\times 28.076 \\\\=(529.9 \pm 3.499 \times 28.076)\\\\=(529.9 \pm 98.238)\\\\=(529.9-98.238, 529.9+98.238)\\\\=(431.662, 628.138)\\\\=(431.6, 628.1)[/tex]

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