展开全部

题目列表

题目内容
The standard deviation of n numbers $$x_{1}$$, $$x_{2}$$, $$x_{3}$$,......, $$x_{n}$$, with mean x is equal to $$\sqrt{\frac{s}{n}}$$, where S is the sum of the squared differences, $$(x_{i}- x)^{2}$$ for 1 ≤ i ≤ n.

The mean and standard deviation of the 17 values in a list are 0 and 40, respectively. If one more value is included in the list, the mean of the 18 values will be 0. The standard deviation of the 18 values will be closest to which of the following?
Working alone at their respective constant rates, an outlet pump can empty a certain tank of water in 7 hours when the tank is initially full, and an inlet pump can fill the tank in 10 hours when the tank is initially empty. Beginning with a full tank, both pumps work simultaneously at their respective constant rates for 1 hour before the inlet pump is shut off. How many more hours would it take the outlet pump working alone to empty the tank?
If a data point is to be chosen at random from those points for which the monthly ice-cream consumption per person is greater than 0.4 pint, what is the probability that the average temperature corresponding to the data point chosen will be lower than 60℉?
Of the 27 data points, P is the point for which the ratio of the monthly ice-cream consumption per person, in pints, to the average temperature,in degrees Fahrenheit,is greatest. Which of the following is closest to the average temperature that corresponds to P?
p is a positive prime number and a divisor of 40.

Quantity A

p

Quantity B

4


共收录:

25000 +道题目

198本备考书籍

最新提问