5. Based on the information above, is there a statistical difference in hours between breakdowns among three machines at a=0.05? (Please answer "yes", "no", or "not enough information")

 1. What is the value of ①?

2. What is the value of②?

3. What is the value of ③?

4. What is the value of ④ (the critical value for statistical testing)?

8. A manufacturer produces a special alloy steel with an average tensile strength of 26,000 psi. A change in the composition of the alloy is said to increase the breaking strength but not affect the standard deviation which is known to be 400 psi. The manufacturer wants to conclude that the tensile strength has increased only if he is 99% sure of this (c = 0.01). If the average tensile strength is increased by as much as 300 psi, the manufacturer wants to err by not detecting the change at most 10% of the time (β = 0. 10). Assume that the z statistic with respect to the type I error is 2.33 and the z statistic with respect to the typeⅡerror is -1.28. The required sample size to meet these conditions is___________.

7. The following time series represents sales of imported cars in a city for the years 20I I through 2017:Suppose we e want to estimate annual sales of imported cars in the year 2018. The expected number of imported car sales is____________.

6. The time elapsed, in minutes, between the placement of an order of pizza and its delivery is random with the density functionSuppose that it takes 15 minutes for the pizza shop to bake pizza once the shop receives the order. The mean of the time it takes for the delivery person to deliver pizza is___________.

5. Suppose that a firm's sales region has been divided into five territories, each of which was judged to have an equal sales potential. The actual sales volume for several sampled days is indicated below.  If the manager of the firm wants to test the significance of the difference between the observed and expected levels of sales, the figure of the appropriate test statistic is_________.

4. A random variable X represents the number of defective mobile phone is a shipment of four iPhones to a local mobile phone store. Assume that each mobile phone is equally likely to be defective or non-defective, and also assume that each mobile phone is defective or non-defective independently of the other mobile phones. Then the expected number of defective mobile phones is_________.

3. Customers enter a restaurant at random at a rate of four per minute. Assume that the number entering this restaurant in any given time interval has a Poisson distribution. The probability that at least two customers enter the restaurant in a given 0.25-minute interval is__________.

110年 - 110 國立臺灣大學_碩士班招生考試_財務金融研究所甲、丙組:商用統計學#105747

110年 - 110 國立中山大學_碩士暨碩士專班招生考試_企管系企管甲班/甲、乙、丙組選考:商用統計學#104450