On average children speak their first word when they are a year old u=12 months A development psychologist argues that showing a baby educational videos will help them learn to talk more quickly in...

On average children speak their first word when they are a year old u=12 months A development psychologist argues that showing a baby educational videos will help them learn to talk more quickly in order to test this theory the psychologist selects a random sample of for newborn children and instructs their parents to show them educational videos an hour a day for one year and to record their child’s ages when they speak their first word. Ages of first word-10,11,12,11 Use a one tailed test A=.01 Compute 50% confidence intervals and r^2