Apsychologist obtains a random sample of 20 mothers in the first trim ester of their pregnancy. the mothers are asked to play mozart in the house at least 30 minutes each day until they give birth. after 5 years, the child is administered an iq test. we know that iqs are normally distributed with a mean of 100. if the iqs of the 20 children in the study result in a sample mean of 104.2, and a sample standard deviation of 14.7, is there evidence that the children have higher iqs? use the α=0.05 level of significance.

An electronics manufacturer wants to know if customers would be interested in a detachable keyboard for their tables and if so, what the most important features would be. the manufacturer partners with an electronics store to include copies of the survey with every purchase at that store for one week. which of the following best explains why this random sample is unlikely to be a good representative sample of tablet owners' preferences for a detachable keyboard? a) one week is likely not enough time to get a large enough sample. b) most people won't bother to send in the survey, which is likely to skew the results c) there is no way to verify whether the responders to the survey actually own a tablet d) the survey is biased because it was conducted through an electronics store, not the general population

The surface area (sa) of a cube with a as the length of each of its sides is given by the formula . if the surface area is known, how can you rewrite the formula to find its side?

The constitution gives congress the power to create federal courts lower than the supreme court higher than the supreme court equal to the supreme court, unaffected by the supreme court.