Answers created by VSH

• Back to user's profile
• Next
• Find the area under the standard normal curve between z=0 and z=3?
  
• What are the range, median, mean, and standard deviation of: {22, 12, 19, 24, 22, 21, 17, 14, 22, 20, 26, 10}?
  
• What is the area between z= 2.11 and z = 2.49?
  
• A federal report stated that 88% of children under 18 were covered by health insurance in 2000. How large a sample is needed to estimate the true proportion of covered children with 90% confidence with a confidence interval of .05 wide?
  
• If 8% of all people in an area are unemployed, what is the probability that in a sample of 200 persons, there are fewer than 10 people who are unemployed?
  
• A contractor is considering a sale that promise a profit of $33,000 with a probability of 0.7 of $16,000 with a probability of 0.3 what is the expected profit?
  
• What is the sample standard deviation formula?
  
• What is the 95% confidence level for the following problem?
  
• How do you make a box-and-whisker plot of the average daily temperatures in Tucson, Arizona, in December: 67, 57, 52, 51, 64, 58, 67, 58, 55, 59, 66, 50, 57, 62, 58, 50, 58, 50, 60, 63?
  
• X. : 1. 3. 6. 7 P(X) : 0.35. Y. 0.15. 0.2 Find the value of y ? Find the mean (expected value ) ? Find the standard deviation ?
  
• What is the z-number associated with a 91% level of confidence? (In two decimal places)
  
• What is the probability of 5 Sunday in the month of October?
  
• For a normal distribution, what is the percentage of data that is between #mu - 0.5 sigma# and #mu + 0.5 sigma#?
  
• Can you determine a standard deviation from just two or three numbers?
  
• What is an example of a continuous random variable?
  
• What's the percentage of area under a normal curve between the mean and -.90 standard deviations below the mean?
  
• Dutchess County, New York, has been experiencing e mean of 35.4 motor vehicle deaths each year. What is the mean number of deaths per day?
  
• A​ 99% confidence interval for the population proportion is left parenthesis nothing comma nothing right parenthesis?
  
• A government's department of transportation reported that in 2009 Airline A led all domestic airlines in on-time arrivals for domestic flights, with a rate of 83.9%. What is the probability that in the next 6 flights, all 6 flights will be on time?
  
• What is the z-value at #alpha = 0.025#?
  
• If a sample size is sufficiently large, should the mean and median significantly differ?
  
• What is a box plot for the numbers? 2,2,3,4,4,4,5,5,5,6,6,7,7,8,9
  
• Is a bell curve symmetric, right-skewed, or left-skewed?
  
• The mean temperature of humans is known to be 36.8°C. The standard deviation of human temperatures is 0.4°C. How do you find the probability that the mean temperature of a sample of 131 people will be greater than 36.9°C?
  
• ? Find the percent of a standard normal model found in the region : #z<1.13#
  
• For the standard normal distribution, what is the probability of obtaining a z value greater than zero?
  
• X is a normally distributed random variable with a mean of 22 and a standard deviation of 5. The probability that X is less than 9.7 is what?
  
• How to solve this problem if their are 8 random sample size, using a 95% confidece level?
  
• In a standard normal distribution, what z value corresponds to 17% of the data between the mean and the z value?
  
• How do you find the probability of #P( z< 1.45)# using the standard normal distribution?
  
• Maura guesses at all 10 questions on a true/false test. How do you find the probability that she got seven correct?
  
• How do you find the mean and the standard deviation of the sampling distribution of ¯X and find an interval containing 95.44% of all possible sample mean returns?
  
• The mean number of miles Mr. Austin drove in six days was 96. The mode was 82. The median was 97. What are possible distances Mr. Austin drove in the 6 days?
  
• An athletic association wants to sponsor footrace.The average time to run the course is 58.6 min, with a s.deviation of 43 min.If the association give certificates to the fastest 20% of the racers, what should the cutoff time be? (normally distribution)
  
• Holly wants to choose 5 different decorative tiles out of 8. If she plans to place the 5 tiles in a row, end to end, in how many different ways can she arrange them, from left to right?
  
• If a team had a probability equal to .8 of winning and if they were to win 17 or more of their remaining 21 games to become champions, what is the probability that they will become champions?
  
• What are the mean and standard deviation of a probability density function given by #Pr(X=k) = (3^ke^-3)/(k!) # for #k in {0,1,2... oo}#?
  
• Anthony enters a fishing contest. After all the fish are measured, it is announced that the mean fish length was 13 inches, with a standard deviation of 4 inches. Anthony's biggest fish measured 19 inches. What is the z-score for his fish's length?
  
• How do you compute the variance of a probability distribution?
  
• What proportion of sample means would fall between a population mean of 600 and a sample mean of 800 if the standard error of the mean was 250? I need to know how to get to the solution. The final answer is: 0.2881?
  
• A test consists of 910 true or false questions. If the student guesses on each question, what is the standard deviation of the number of correct answers?
  
• Mean=400 SD=50 For a sample of 25 people, what is the probability for 405 to 425?
  
• The probability that a DVD player produced by VCA Television is defective is estimated to be 0.07. A sample of ten players is selected at random. What is the probability that the sample contains no defective units?
  
• How do you write the equation of the regression line for the following set of data and find the correlation coefficient?
  
• What is the probability that the sample mean will be below 0.95 centimeters?
  
• In a normal distribution with a mean of 10 pounds and a standard deviation of 5 pounds, what would the probability be that a person would gain at least 2 pounds?
  
• What is need the mean of 18, 24, 67, 53, 36, 64, 124, 91, 101, 106, 102, 127? What are 2 standard deviations above and below the mean?
  
• A collection of 22 laptops includes 6 defective laptops. If a sample of 3 laptops is randomly chosen from the collection, what is the probability that at least one laptop in the sample will be defective?
  
• What are the mean and standard deviation of a binomial probability distribution with #n=69 # and #p=5/23 #?
  
• A data set has a variance of 0.16. What is the standard deviation of the data set?
  
• Where will a prediction interval or a confidence interval be narrower: near the mean or further from the mean?
  
• Sociologists say that 95% of married women claim that their husband's mother is the biggest bone of contention in their marriages. Suppose that six married women are having coffee together. What's the probability none of them dislike their mother-in-law?
  
• IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. What percentage of people have an IQ score between 103 and 136, to the nearest tenth?
  
• A sample of 64 observations is selected from a normal population. The sample mean is 215, and the population standard deviation is 15. Conduct the following test of hypothesis using the .03 significance level. What is the p-value?
  
• One card is selected at random from a standard deck of cards of 52. what is the probablity that the card selected is red or picture card?
  
• Can you calculate the probability that a randomly chosen freshman studies more than 9 hours? If not, explain why not. (Use information given below)
  
• A normal distribution has a mean of 140 and a standard deviation of 40. How do you calculate a percentile rank of a score of 172?
  
• If the probability of the event "It will rain today" is 0.6, what is the probability of the complement event?
  
• A line of best fit predicts that when #x# equals 35, #y# will equal 34.785, but #y# actually equals 37. What is the residual in this case?
  
• What is the median age of the 7 whose ages are 11,10,13,11,12,16,14?
  
• Two dice are rolled. Find the probability that the faces are different given that the dice show sum of 10?
  
• The average age of a college professor is normally distributed with a mean of 40 years and a standard deviation of 8 years. What is the probability that a teacher is older than 50?
  
• Let #X ~ N(4, 16)#. How do you find #P(X > 0)#?
  
• The heights of women at a large university are approximately bell-shaped, with a mean of 65 inches and standard deviation of 2.5 inches. What is the probability that two randomly selected women are 62.5 inches or shorter?
  
• What is the Z-score that has 78.52% of the distribution's area to the right?
  
• In a certain town, 10% of people commute to work by bicycle. If a person is selected randomly from the town, what are the odds against selecting someone who commutes by bicycle?
  
• How do you extrapolate using a linear regression line?
  
• How do you find the margin error for a 90% confidence level with n = 480, x = 130?
  
• What is the mean of the following numbers: 77, 81, 75, 67, 65, 65, 60, 64, 69, 71, 65, 81?
  
• Once you have a z-score, how do you calculate the value that is found in the z-tables?
  
• When transforming a nonstandard distribution to a standard distribution, what formula is used to convert a value into a z score?
  
• What is the critical value zalpha/2 that corresponds to 93% confidence level?
  
• Consider Bernoulli trials with success probability p=1/4. Given that the first four trials result in all failures, what is the conditional probability that the next four trials are all successes?
  
• A set of data has a mean of 127 and a standard deviation of 15. What is the #z#-score of #x=118#?
  
• Suppose #X# has a Poisson distribution with a mean of .4. How would i find the probability when #X=0, X=4, X<= 2,# and when #X=8#?
  
• A proffesional wishes to estimate the birth weights of a baby. How large a sample must she select if she decides to be 99% confident that the true mean is within 10 ounces of the sample mean? The standard deviation of the birth weights is 4 ounces.
  
• A study of 36 camels showed that they could walk an average rate of 4.2 km/hr. the sample standard deviation is .64. Find the 90% confidence interval for mean of all camels?
  
• A sample of 50 days showed that a fast food restaurant serve an average of 182 customers during lunch (between 11am-2 pm). The standard deviation of the sample is 8. Find the 95% confidence interval for the mean?
  
• How do you find the margin of error with n = 163, x = 96, and a 95% confidence interval?
  
• How do you find the z-scores that separate the middle 41% of the distribution from the tails of a standard normal distribution?
  
• Find the area under the standard normal curve that lies outside the interval between z= -2.2 and z= -1.3?
  
• In a survey of 1118 people, 732 people said they voted in a recent presidential election. Given that 63% of eligible voters actually did vote, what is the probability that among the 1118 randomly selected voters , at least 732 actually did vote?
  
• In measuring reaction time, a psychologist estimates that a standard deviation is .05 seconds. How large a sample of measurements must he take in order to be 95% confident that the error in his estimate of mean reaction time will not exceed 0.01 seconds?
  
• Body temperatures of adults are normally distributed with a mean of 98.6°F and a standard deviation of 0.6°F. If 30 adults are randomly selected, what is the probability that their mean body temperature is less than 98.9°F?
  
• Does the following example fit the principle of Correlation vs. Causation?
  
• A population has a mean of μ = 100 and a standard deviation of σ = 10. If a single score is randomly selected from this population, how much distance, on average, should you find between the score and the population mean?
  
• A survey of 300 fatal accidents showed that 123 were alcohol related. construct a 95% confidence interval for the proportion of fatal accidents that were alcohol related?
  
• A distribution has mean = 70 and SD = 20. What is the probability of getting a score value that is less than 75?
  
• what is the minimum sample needed if he wants to be 99% confident that the true average time is within 15 minutes of the sample average? Assume the standard deviation of all times is 30 minutes.
  
• The resting heart rates for a sample of individuals are normally distributed with a mean of 70 and a standard deviation of 15. How do you find the percentage of heart rates less than 85?
  
• How do you find the median in box plots?
  
• What is the standard deviation of {7, 2600, 7, 8, 7, 7}?
  
• How do you Find the​ z-scores that separate the middle 85% of the distribution from the area in the tails of the standard normal distribution?
  
• What percent of cases fall between the mean and –1 to +1 standard deviations from the mean?
  
• De Guzman Co. Claims that the average life of their battery product last of 26 hours with a standard deviation of 5 hours. What is the probability that 35 random pieces of their batteries have an average life span of less than 24.3 hours?
  
• What is the central limit theorem?
  
• As sample size increases, what happens to the standard error of M?
  
• What is the area under the standard normal distribution between z = -1.69 and z = 1.00
  
• Assume that IQ scores are normally distributed, with a mean #mu# of 100 and standard deviation #sigma# of 15. What is the IQ score that separates the IQ scores of the lowest 25% from the rest?
  
• Use the empirical rule to determine the approximate probability that a z value is between -1 and 1 on the standard normal curve.
  
• Next