(Solved): Autistic children often have a small head circumference at birth, followed by a sudden and excessiv ...

Autistic children often have a small head circumference at birth, followed by a sudden and excessive increase in head circumference during the first year of life. A recent study \( { }^{1} \) examined the brain tissue in autopsies of seven autistic male children between the ages of 2 and 16 . The mean number of neurons in the prefrontal cortex in non-autistic male children of the same age is about 115 billion. The prefrontal cortex is the part of the brain most disnupted in autism, as it deals with language and social communication. In the sample of seven autistic children, the mean number of neurons in the prefrontal cortex was \( 1.94 \) billion with a standard deviation of o 50 billion. The values in the sample are not heavily skewed. Use the t-distribution to test whether this sample provides evidence that autisticmale children have more neurons (on average) in the prefrontal cortex than non-autistic children. (This study indicates that the causes of autism may be present before birth) "Adapted from Courchesne, E. et al. "Neuron Number and Size in Prefrontal Cortex of Children with Autiem" Journol of the American Medical Association, November 2011: 306/18): 2001-2010. Give the teststatistic and the p-value and state the conclusion of the test. Round your answer for the test statistic to two decimal places and your answer for the p-value to three decimal places. test statistic \( = \) D.valise = Conclusion: