The life in hours of a 75-watt light bulb is known to be normally distributed with σ = 22 hours. a random sample of 20 bulbs has a mean life of x overscript bar endscripts = 1012 hours. suppose that we wanted the total width of the two-sided confidence interval on mean life to be six hours at 95% confidence. what sample size should be used? round up the answer to the nearest integer.

The magnitude, m, of an earthquake is defined to be m=log l/s, where i is the intensity of the earthquake (measured by the amplitude of the seismograph wave) and s is the intensity of a “standard” earthquake, which is barely detectable. what is the magnitude of an earthquake that is 1,000 times more intense than a standard earthquake? use a calculator. round your answer to the nearest tenth.

17. a researcher measures three variables, x, y, and z for each individual in a sample of n = 20. the pearson correlations for this sample are rxy = 0.6, rxz = 0.4, and ryz = 0.7. a. find the partial correlation between x and y, holding z constant. b. find the partial correlation between x and z, holding y constant. (hint: simply switch the labels for the variables y and z to correspond with the labels in the equation.) gravetter, frederick j. statistics for the behavioral sciences (p. 526). cengage learning. kindle edition.

Use this graph to find the cost of 6 show tickets