Pdf of the uniform distribution between 0 and 10 with expected value of 5. The distribution is ______________ (name of distribution). P(A or B) = P(A) + P(B) - P(A and B). 2 If you are waiting for a train, you have anywhere from zero minutes to ten minutes to wait. 11 233K views 3 years ago This statistics video provides a basic introduction into continuous probability distribution with a focus on solving uniform distribution problems. (a) What is the probability that the individual waits more than 7 minutes? Thank you! Let k = the 90th percentile. The 90th percentile is 13.5 minutes. As waiting passengers occupy more platform space than circulating passengers, evaluation of their distribution across the platform is important. However, there is an infinite number of points that can exist. 150 hours and \(\sigma =\sqrt{\frac{{\left(41.5\right)}^{2}}{12}}=0.7217\) hours. Formulas for the theoretical mean and standard deviation are, \[\sigma = \sqrt{\frac{(b-a)^{2}}{12}} \nonumber\], For this problem, the theoretical mean and standard deviation are, \[\mu = \frac{0+23}{2} = 11.50 \, seconds \nonumber\], \[\sigma = \frac{(23-0)^{2}}{12} = 6.64\, seconds. This means that any smiling time from zero to and including 23 seconds is equally likely. The sample mean = 7.9 and the sample standard deviation = 4.33. Find the average age of the cars in the lot. A continuous random variable X has a uniform distribution, denoted U ( a, b), if its probability density function is: f ( x) = 1 b a. for two constants a and b, such that a < x < b. As one of the simplest possible distributions, the uniform distribution is sometimes used as the null hypothesis, or initial hypothesis, in hypothesis testing, which is used to ascertain the accuracy of mathematical models. 2.75 State the values of a and b. = Find the probability that a different nine-year old child eats a donut in more than two minutes given that the child has already been eating the donut for more than 1.5 minutes. A. \(f(x) = \frac{1}{4-1.5} = \frac{2}{5}\) for \(1.5 \leq x \leq 4\). \(f(x) = \frac{1}{15-0} = \frac{1}{15}\) for \(0 \leq x \leq 15\). 2 Discrete and continuous are two forms of such distribution observed based on the type of outcome expected. )( A student takes the campus shuttle bus to reach the classroom building. The interval of values for \(x\) is ______. 11 Refer to [link]. 2 You must reduce the sample space. and The data in (Figure) are 55 smiling times, in seconds, of an eight-week-old baby. 15 The probability that a randomly selected nine-year old child eats a donut in at least two minutes is _______. 1), travelers have different characteristics: trip length l L, desired arrival time, t a T a, and scheduling preferences c, c, and c associated to their socioeconomic class c C.The capital and curly letter . k=(0.90)(15)=13.5 You are asked to find the probability that an eight-week-old baby smiles more than 12 seconds when you already know the baby has smiled for more than eight seconds. \(a = 0\) and \(b = 15\). We are interested in the weight loss of a randomly selected individual following the program for one month. You are asked to find the probability that an eight-week-old baby smiles more than 12 seconds when you already know the baby has smiled for more than eight seconds. P(B) Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. Use the following information to answer the next eleven exercises. In this distribution, outcomes are equally likely. When working out problems that have a uniform distribution, be careful to note if the data is inclusive or exclusive of endpoints. Write the random variable \(X\) in words. First way: Since you know the child has already been eating the donut for more than 1.5 minutes, you are no longer starting at a = 0.5 minutes. The probability that a randomly selected nine-year old child eats a donut in at least two minutes is _______. I'd love to hear an explanation for these answers when you get one, because they don't make any sense to me. When working out problems that have a uniform distribution, be careful to note if the data are inclusive or exclusive of endpoints. = The probability that a randomly selected nine-year old child eats a donut in at least two minutes is _______. Not all uniform distributions are discrete; some are continuous. = 238 A continuous uniform distribution is a statistical distribution with an infinite number of equally likely measurable values. Find the mean and the standard deviation. a. The uniform distribution is a probability distribution in which every value between an interval from a to b is equally likely to occur. Sketch the graph, and shade the area of interest. Possible waiting times are along the horizontal axis, and the vertical axis represents the probability. The mean of uniform distribution is (a+b)/2, where a and b are limits of the uniform distribution. (a) The solution is \(f\left(x\right)=\frac{1}{8}\) where \(1\le x\le 9\). c. Find the 90th percentile. Question 3: The weight of a certain species of frog is uniformly distributed between 15 and 25 grams. \(X \sim U(0, 15)\). Introduction to Statistics is our premier online video course that teaches you all of the topics covered in introductory statistics. Note that the shaded area starts at \(x = 1.5\) rather than at \(x = 0\); since \(X \sim U(1.5, 4)\), \(x\) can not be less than 1.5. What does this mean? The total duration of baseball games in the major league in the 2011 season is uniformly distributed between 447 hours and 521 hours inclusive. = 2 Find the probability that the commuter waits less than one minute. Find the probability that she is over 6.5 years old. 1.5+4 for 0 X 23. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Statology is a site that makes learning statistics easy by explaining topics in simple and straightforward ways. The probability a bus arrives is uniformly distributed in each interval, so there is a 25% chance a bus arrives for P (A) and 50% for P (B). 12 The graph of the rectangle showing the entire distribution would remain the same. 2 Then x ~ U (1.5, 4). (k0)( 2 2 k=(0.90)(15)=13.5 1 = \(\frac{15\text{}+\text{}0}{2}\) It is assumed that the waiting time for a particular individual is a random variable with a continuous uniform distribution. The data follow a uniform distribution where all values between and including zero and 14 are equally likely. What is the height of \(f(x)\) for the continuous probability distribution? (15-0)2 (a) The probability density function of X is. and Structured Query Language (known as SQL) is a programming language used to interact with a database. Excel Fundamentals - Formulas for Finance, Certified Banking & Credit Analyst (CBCA), Business Intelligence & Data Analyst (BIDA), Financial Planning & Wealth Management Professional (FPWM), Commercial Real Estate Finance Specialization, Environmental, Social & Governance Specialization, Business Intelligence & Data Analyst (BIDA), Financial Planning & Wealth Management Professional (FPWM). Buses run every 30 minutes without fail, hence the next bus will come any time during the next 30 minutes with evenly distributed probability (a uniform distribution). What is the expected waiting time? A distribution is given as X ~ U(0, 12). Find the probability that a randomly selected furnace repair requires more than two hours. f (x) = \(\frac{1}{15\text{}-\text{}0}\) = \(\frac{1}{15}\) Find the mean and the standard deviation. Answer: a. For the first way, use the fact that this is a conditional and changes the sample space. \(P(x > 2|x > 1.5) = (\text{base})(\text{new height}) = (4 2)(25)\left(\frac{2}{5}\right) =\) ? Since 700 40 = 660, the drivers travel at least 660 miles on the furthest 10% of days. P(0 < X < 8) = (8-0) / (20-0) = 8/20 =0.4. Find the probability that a person is born at the exact moment week 19 starts. As an Amazon Associate we earn from qualifying purchases. Step-by-step procedure to use continuous uniform distribution calculator: Step 1: Enter the value of a (alpha) and b (beta) in the input field Step 2: Enter random number x to evaluate probability which lies between limits of distribution Step 3: Click on "Calculate" button to calculate uniform probability distribution What percentile does this represent? 3 buses will arrive at the the same time (i.e. For the second way, use the conditional formula from Probability Topics with the original distribution \(X \sim U(0, 23)\): \(P(\text{A|B}) = \frac{P(\text{A AND B})}{P(\text{B})}\). Example 1 The data in the table below are 55 smiling times, in seconds, of an eight-week-old baby. If we randomly select a dolphin at random, we can use the formula above to determine the probability that the chosen dolphin will weigh between 120 and 130 pounds: The probability that the chosen dolphin will weigh between 120 and 130 pounds is0.2. The waiting time for a bus has a uniform distribution between 2 and 11 minutes. 3.375 hours is the 75th percentile of furnace repair times. The percentage of the probability is 1 divided by the total number of outcomes (number of passersby). ( The 30th percentile of repair times is 2.25 hours. Is this because of the multiple intervals (10-10:20, 10:20-10:40, etc)? \(X\) is continuous. ( b is 12, and it represents the highest value of x. 1 )=0.90 Use the conditional formula, \(P(x > 2 | x > 1.5) = \frac{P(x > 2 \text{AND} x > 1.5)}{P(x > 1.5)} = \frac{P(x>2)}{P(x>1.5)} = \frac{\frac{2}{3.5}}{\frac{2.5}{3.5}} = 0.8 = \frac{4}{5}\). Write the probability density function. The standard deviation of \(X\) is \(\sigma = \sqrt{\frac{(b-a)^{2}}{12}}\). The 30th percentile of repair times is 2.25 hours. = 2 15 \(P\left(x