posted by Norvin on .
Reading readiness of preschoolers from an impoverished neighborhood (=20) was measured using a standardized test. Nationally, the mean on thios test for preschoolers is 30.9, with SD = 2.08.
a. children below the 30th percentile (in the bottom 30%) are in need of special assistance prior to attending school. What raw score marks the cut-off score for these children?
You can look up a normal distribution table to find that the z-score for the lower 30 percentile is z=-0.475.
Score = μ+σz to get the raw score. Remember that the value of z is signed.