1. In the Chicago area, the price of new tires is normally distributed with a standard deviation of = $ A random sample of 64 tires indicates a mean selling price of x = $ Construct an 85% confidence interval for the mean selling price, µ of this new tire in the Chicago area. In order to estimate within $10.00 of the population mean, how large of a sample should be taken in order to be 95% confident of achieving this level of accuracy
2. Fifty electric bills from the apartment of a certain city apartment are chosen at random. The mean electric bill was x = $ with s = $ The electric bills have a normal distribution. Construct a 98% confidence interval for P
3. Thirty SAT scores were chosen at random from the records of seniors at a certain high school over the last 20 years Construct a 95% confidence interval for the population mean µ
A random sample on n = 100 voters in a community produced x = 59 voters in favor of a candidate A. Estimate the fraction of the voting population favoring candidate A using a 95% and a 90% confidence interval.
How many people must be asked if candidate A wants A 95% confidence interval with a margin of error of + 3 %?
A recent poll cited that 76 out of 180 randomly chosen Households watch at least 2 hours of public television per week. Find a 90% confidence interval for p, the proportion of households that watch at least 2 hours of public television per week.
How many people must be asked if the station wants a 90% confidence interval with a margin of error of + 4 %?
1.A manufacturer of gunpowder claims to have developed a gun powder that is designed to produce a muzzle velocity of 3000 ft sec. The following data is collected in ft/sec Construct a 95% and a 85% confidence interval for µ.
1.The profit for a car dealership for the past week was $210 $300 $120 $620 $450 $510 Construct a 90% confidence interval for the average pofit