The table below lists weights (carats) and prices (dollars) for randomly selected diamonds. Is there sufficient evidence to suggest that there is a linear correlation between weights and prices? Construct a scatterplot, and find the value of the linear correlation coefficient r. Also find the P-value or the critical values of r using α = 0.05.

Respuesta :

Answer:

Step-by-step explanation:

Hello!

Given the variables

X₁: Weight of a diamond (carats)

X₂: Price of a diamond (dollars)

You have to test if there is any correlation between the two variables, the hypotheses are:

H₀: ρ = 0

H₁: ρ ≠ 0

α: 0.05

The resulting correlation coefficient is

r= 0.97

I've used statistics software to calculate the correlation coefficient. To do so manually you have to use the following formula:

[tex]r= \frac{sumX_1X_2-\frac{(sumX_1)(sumX_2)}{n} }{[sumX_1^2-\frac{(sumX_1)^2}{n} ][sumX_2^2-\frac{(sumX_2)^2}{n} ]}[/tex]

The statistic for the parametric test is

[tex]t= \frac{r\sqrt{n-2} }{\sqrt{(1-r^2)} } = \frac{0.97\sqrt{6-2} }{\sqrt{(1-(0.97^2))} } = 7.98[/tex]

p-value 0.0016

The p-value is less than the level of significance, so the decision is to reject the null hypothesis.

Then at a 5% significance level, you can conclude that there is a linear correlation between the weight in carats of the diamonds and their price in dollars.

The scatterplot in the attachment.

I hope you have a SUPER day!

Ver imagen cchilabert
Ver imagen cchilabert