1) What type of variable cannot take a value of a fraction between two consecutive sample points? a) discrete b) continuous c) qualitative d) quantitative 2) Which of the following is a discrete variable? a) Length of time of a telephone call b) Age of employees in a certain company c) Number of marriages last year d) weight of newborn babies in a hospital 3) Which of the following is not a true statement? a) The value of the random variable could be zero.  b) Random variables can only have one value. c) The probability of the value of a random variable could be zero. d) The sum of all the probabilities in a probability distribution is always equal to one. 4) Which of the following is not a probability function of a probability distribution? a) P(X=x): 0.1, 0.25, 0.15, 0.35, 0.15 b) P (X=x): 2/4,1/4,2/4,1/4 c) P (X=x): 20%, 50%, 15%, 15% d) P (X=x): 2/7,2/7,4/14,2/14 5) If P(X) = X/6 , what are the possible values of X for it to be a probability distribution? a) 0, 2, 3 b) 1, 2, 3 c) 2, 3, 4 d) 1, 1, 2 6) What is the degree to which random value differ from the expected value? a) A. Mean b) B. variance c) C. standard deviation d) D. range 7) Which of the following statements is true? a) The value of mean in Standard Normal Distribution is 0. b) The standard deviation in Standard Normal Distribution is always 2. c) The area under the normal curve is 50%. d) Sometimes, the area under the normal curve is negative. 8) What is the z-score of x=12 if μ=15.3 and σ=3? a) 1.11 b) -1.11 c) -1.10 d) 1.10 9) What is the probability that a randomly selected value lies between 115 to 125 if the mean is 100 with a standard deviation of 15? a) A. 58.99% b) B. 34.13% c) C. 24.86% d) D. 11.12% 10) Which of the following problems illustrates a random sampling technique? a) Animals going astray are to be observed. b) Ten names of students were picked out from a box containing 1,000 names written in rolled paper. c) Respondents are chosen from a list in the telephone directory. d) Minority group of senators are to be interviewed. 11) Which of the following is an example of parameter? a) A teacher randomly selected 15 students from her class. These 15 students were asked to go to the auditorium to be interviewed by a researcher. b) In a study concerning the economic status of employees in a certain company, a researcher randomly selected 45 employees. c) The Philippine Senate has 24 senators. d) Jupiter has 67 confirmed moons. 12) A certain population has a mean of 15.4 and a standard deviation of 5.6. If random samples of size 5 is taken from a population, which of the following statements is true? a) The mean of the sampling distribution of the sample means is equal to 15.4. b) The mean of the sampling distribution of the sample means is less than 15.4. c) The standard deviation of the sampling distribution of the sample mean is 5.6. d) The standard deviation of the sampling distribution of the sample mean is 15.5. 13) An unknown distribution has a mean of 90 and a standard deviation of 15. Samples of size n = 25 are drawn randomly from the population. Find the average value that is 2 standard deviations above the mean of the averages. a) 90 b) 92 c) 94 d) 96 14) What is the shape of the sampling distribution of the means if random samples of size n become larger? a) Left skewed b) Normal c) Rectangular d) Right skewed 15) Which of the following statements is not true regarding the standard error of the mean? a) It is less than the standard deviation of the population.  b) It decreases as the sample size increases. c) It measures the variability of the mean from sample to sample. d) It is equal to the mean of the sampling distribution. 16) Which sample size will give a smaller standard error of the mean? a) 12 b) 20 c) 25 d) 35 17) The ___________ is a range of values that contains the parameter value. a) confidence limits b) confidence interval c) confidence coefficient d) confidence level 18) What do you call a single value that may refer to a parameter value? a) z statistic b) t statistic c) Point estimate d) Interval estimate 19) Under which of the following circumstances is it impossible to construct a confidence interval for the population mean? a) A non-normal population with a large sample and an unknown population variance b) A normal population with a large sample and a known population variance c) Non-normal population with a small sample and an unknown population variance d) A normal population with a small sample and an unknown population variance 20) When n ≥ 30 and the population standard deviation is known, what is the appropriate distribution? a) z b) t c) p d) r 21) Which of the following is not a property of the t distribution? a) As the sample size increases, it gradually approaches the normal distribution b) It is symmetric c) Its exact shape is characterized by the “degrees of freedom.” d) All of the above are properties of the t distribution. 22) In a t distribution, the critical values are based on ______. a) n b) z c) t d) df 23) What is the 2.5th and 97.5th percentile on a t-distribution with 6 degrees of freedom? a) ±2.447 b) ±2.571 c) ±3.143 d) ±3.707 24) A random sample of 30 items is selected from a population with a standard deviation of 10. If the sample mean is 52, the 95% confidence interval to estimate the population mean is? a) 49.0 to 55.0 b) 47.9 to 56.1 c) 49.7 to 54.3   d) 48.4 to 55.6 25) When estimating the population mean with a small sample, the t distribution may be used with how many degrees of freedom? a) n – 1 b) n/2 c) n d) n + 1 26) When X = 50 and n = 215, what is the value of p̂? a) 0.23 b) 4.3 c) 50 d) 215 27) A randomly selected sample of 1,000 college students was asked whether they had ever used drugs. Sixteen percent (16% or 0.16) of the 1,000 students surveyed said they had. Which one of the following statements about the number 0.16 is correct? a) It is a sample proportion. b) It is a population proportion. c) It is a margin of error. d) It is a randomly chosen number. 28) Suppose a 95% confidence interval for the proportion of Filipinos who exercise regularly is 0.29 to 0.37. Which one of the following statements is FALSE? a) It is reasonable to say that more than 25% of Filipinos exercise regularly. b) It is reasonable to say that more than 40% of Filipinos exercise regularly. c) The hypothesis that 33% of Filipinos exercise regularly cannot be rejected. d) It is reasonable to say that fewer than 40% of Filipinos exercise regularly 29) For numbers 29-30, refer to the following situation.The mean gasoline consumption of 10 cars is 28 liters. Find the point and the interval estimates using 95% confidence level.What is the appropriate distribution? a) Z b) t c) p d) s 30) The lower limit is approximately _______. a) 27 b) 85 c) 26.81 d) 26.68

Statistics and Probability

打印
嵌入

排行榜

视觉风格

选项

切换模板

恢复自动保存：？