Autistic children often have a small head circumference at birth, followed by a

Question

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 study1 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 1.15 billion. The prefrontal cortex is the part of the brain most disrupted 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 0.50 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.)

a) state the null and alternative hypotheses

b) state the test statistic and p-value

Explanation / Answer

Ho : miu = 1.15

Ha : miu > 1.15

t = ( 1.94 - 1.15 ) / (0.50 / srqt 7)

t = 4.18

p value : 0.0025

p value is calculated in a program because is a t test hypotheses

since p value is very lower we reject Ho

conclusion

the sample providence evidence that autisticmale children have more neurons (on average) in the prefrontal cortex than non-autistic children

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