To rewrite the formula to x is a function of y. we have to add 2y to both sides of the formula. Instead of adding 2y, Lucia subtracted 2y from the right side.
Instead of what she did, x should be written the following way
First ask yourselfhat needs to be dristributed. That would be -1 (x-9) To distribute you have to multiply the number out side of the parentheses (-1) by each term inside the parentheses( x and -9) -1×x=-x -1×-9=9 Now the expression is -x+9+4x To simplify you have to combine like terms (4x and-x) 4x-x=3x Your answer is 9+3x or 3(3+x).
d. There is a 98% chance that the true proportion of customers who click on ads on their smartphones is between 0.56 and 0.62.
Step-by-step explanation:
Confidence interval:
x% confidence
Of a sample
Between a and b.
Interpretation: We are x% sure(or there is a x% probability/chance) that the population mean is between a and b.
In this question:
I suppose(due to the options) there was a small typing mistake, and we have a 98% confidence interval between 0.56 and 0.62.
Interpreation: We are 98% sure, or there is a 98% chance, that the true population proportion of customers who click on ads on their smartphones is between 0.56 and 0.62. Option d.