Anna has bought a new toaster. It has a dial that allows her to set the 'strength' of toasting. She is not sure if it works very well and decides to run SOme experiments. She sets the dial to various values, :12, and measures how long the toaster cooks the bread, Y, before it pops the bread out. She does a simple linear regression analysis of these data using the model E(Y | :6) = o: + 63: and va.r{Y | 1:) = 02. Some partial R output from her analysis is shown below (the parts shown as ' ('?)' have been omitted from the output). Estimate Std. Error t value Pr(>|t|) (Intercept) -0.7323 1.8852 (?) (?) x 1.1556 0.3818 C?) (?) Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1 Residual standard error: 1.686 on 28 degrees of freedom Multiple R-squared: 0.2465, Adjusted R-squared: 0.2196 F-statistic: 9.159 on 1 and 28 DF, p-value: 0.005262 (a) How many experiments did Anna carry out? Explain how you determined this. (b) What is Anna's estimate of a"