Select all possible solutions for 2x+7 ≤ 3x-5 -14 -23 -261 12 18 24 107

2x+7 <= 3x-5

subtract 2x from each side

7 <= x-5

add 5 to each side

12 <= x

x must be greater than or equal to 12

12 18 24 and 107 are possible solutions

a) We can be 95% sure that true average age (in weeks) at which babies begin to crawl is between 30.65 weeks and 32.89 weeks.

b) Margin of error for the confidence interval is 1.12 weeks.

Step-by-step explanation:

Let m be the estimate of the average age (in weeks) at which babies begin to crawl

Let ME be the margin of error.

then the difference between the upper bound and the lower bound gives:

m+ME - (m-ME) = 2ME = 32.89-30.65=2.24 which gives

ME=1.12 weeks