In a recent Gallup poll, telephone interviews were conducted…

In a recent Gallup poll, telephone interviews were conducted with a random sample of 1,018 U.S. adults.  Of those interviewed, 285 said they would spend less on holiday gifts this year than they did last year.  The margin of error was 0.018.  What confidence level did the pollster use?

Computer programs are available that produce “random numbers…

Computer programs are available that produce “random numbers” which are used in simulation studies of the sampling distributions of statistics.  One researcher used a computer program to generate 100 single-digit integers (0 through 9) and tabulated the frequency with which each occurred.  One concern is whether the computer program could be expected (in the “long run”) to produce equal numbers of each integer.  The table below summarizes the observed and expected frequencies. What is the minimum value of the Chi-Square that would lead to the conclusion that the computer program was defective (that is, P-value < 0.05)?

Match the alga to its description This heterotrophic genus i…

Match the alga to its description This heterotrophic genus is known to cause a skin infection in humans and mastitis in cattle. [alga1] This heterotrophic genus infects insects by releasing a filament that penetrates the host’s gut. [alga2] This photosynthetic genus is often an endosymbiont. [alga3] The photosynthetic genus produces lipids and hydrocarbons which have contributed to oil deposits. [alga4]