The amount of time Mary spends on the phone each month can be thought of as a random variable that is approximately normal distributed. Mary spends an average of 40 hours on her phone with a standard deviation of 4 hours. Find the probability that Mary spends between 30 and 40 hours on the phone.​

How many verticies does a triangular prims have

Unaware that 35% of the 10000 voters in his constituency support him, a politician decides to estimate his political strength. a sample of 200 voters shows that 40% support him. a. what is the population? b. what is the parameter of interest? state its value c. what is the statistics of the interest? state its value d. compare your answers in (b) and (c) is it surprising they are different? if the politician were to sample another 200 voters, which of the two numbers would most likely change? explain

Why is it so easy to buy on impulse and overspend with a credit card? what could you do to counteract this tendency?