Question

大学数学题 求大神帮忙 越快越好

1.This exercise uses the normal probability density function and requires the use of either technology or a table of values of the standard normal distribution.
Repeated measurements of a student's IQ yield a mean of 115, with a standard deviation of 10. What is the probability that the student has an IQ between 113 and 117? (Round your answer to four decimal places.)

2.This exercise uses the normal probability density function and requires the use of either technology or a table of values of the standard normal distribution.
The cash operating expenses of the regional phone companies during the first half of 1994 were distributed about a mean of $29.87 per access line per month, with a standard deviation of $2.95. Company A's operating expenses were $28.00 per access line per month. Assuming a normal distribution of operating expenses, estimate the percentage of regional phone companies whose operating expenses were closer to the mean than the operating expenses of Company A were to the mean. (Round your answer to two decimal places.)

3.Assuming that workers' salaries in your company are uniformly distributed between $20,000 and $70,000 per year, calculate the average salary in your company.
麻烦写下步骤

Answer 1

第3题，题里说工资均匀分布在[20k,70k]，计算平均工资=(20000+70000)/2=45000
前两个题英语太长了！

追问

谢谢啊 其实我有大概过程 只是里面有一些不懂 能不能私聊帮我看看 感谢

Answer 2

大哥，发题啊，没题何解？

Answer 3

啥问题？？？

Answer 4

题呢？看不到、

Answer 5

问题在哪哟