The level of nitrogen oxides (NOX) in the exhaust of a particular car model varies with mean 0.7 grams per mile and standard deviation 0.17 grams per mile . (a) What sample size is needed so that the standard deviation of the sampling distribution is 0.01 grams per mile ? ANSWER: (b) If a larger sample is considered, the standard deviation for x would be (NOTE: Enter "SMALLER","LARGER" or "THE SAME" without the quotes.)

The acidity of liquids is measured by pH on a scale of 0 to 14. Distilled water has pH 7.0, and lower pH values indicate acidity. Normal rain is somewhat acidic, so "acid rain" is sometimes defined as rainfall with a pH below 5.0.The pH of rain at one location varies among rainy days according to a Normal distribution with mean 5.53 and standard deviations 0.64.

For a data set of the pulse rates for a sample of adult females, the lowest pulse rate is 33 beats per minute, the mean of the listed pulse rates is x =74.0 beats per minute, and their standard deviation iss = 13.2 beats per minute. a. What is the difference between the pulse rate of 33 beats per minute and the mean pulse rate of the females? b. How many standard deviations is that [the difference found in part (a)]? c. Convert the pulse rate of 33 beats per minutes to a z score. d. If we consider pulse rates that convert to z scores between -2 and 2 to be neither significantly low nor significantly high, is the pulse rate of 33 beats per minute significant? a. The difference is beats per minute. (Type an integer or a decimal. Do not round.) b. The difference is standard deviations. (Round to two decimal as needed.) c. The z score is z= (Round to two decimal places as needed.) d. The lowest pulse rate is

A population has a mean = 73 and a standard deviation σ = 22. Find the mean and standard deviation of a sampling distribution of sample means with sample size n=240. 1x = (Simplify your answer.)

The diameter of a spindle in a small motor is supposed to be 4.4 millimeters (mm) with a standard deviation of 0.11 mm. If the spindle is either too small or too large, the motor will not work properly. The manufacturer measures the diameter in a sample of 15 spindles to determine whether the mean diameter has moved away from the required measurement. Suppose the sample has an average diameter of 4.27 mm. H0: Ha: (b) Harry thinks that prices in Caldwell are lower than the rest of the country. He reads that the nationwide average price of a certain brand of laundry detergent is $20.95 with standard deviation $0.78. He takes a sample from 5 local Caldwell stores and finds the average price for this same brand of detergent is $18.31. H0: Ha:

The weights for a baby boy is normally distributed with a mean score of 7lbs and a standard deviation of 0.8lbs. determine the following:

The president of a college wants to determine the mean number of units that college students take per semester. How large of a sample is required in order to be 99% sure that a sample mean will be off by no more than 1.25 units? An initial study suggested that the standard deviation is approximately 2.1 units.