One of the Most Striking Human Accomplishments Is the Achievement

Essay

One of the most striking human accomplishments is the achievement of intelligible speech by age five. Deficits in speech acquisition often occur when a child has hearing difficulty or does is slow to develop the motor functions associated with speech. Other deficits in speech acquisition are of unknown origin. It has been hypothesized that a family history of speech communication disorder might be a factor in speech delay. The theory is that if members of the family have difficulty communicating, this may increase the probability of a speech deficit in a young family member. A random sample of healthy two-year-olds was followed over the course of a year. At age 3, each child was classified as having a speech delay or not. These data, cross-classified by a family history of speech communication disorder, is given in the table below: ​ a) At the .05 significance level, do the data provide evidence of the hypothesized developmental differences? Provide statistical evidence for your conclusion. b) Is this an observational or experimental study? Justify your response in a few sentences.