Listening 3 (4 points)   Question: What year is the student?

Sección: Pruebas de hipótesis: proporción y dos muestrasSe contrasta si la tasa de resolución supera el estándar institucional de 80%: H₀: p = 0.80 frente a H₁: p ≠ 0.80, mediante una prueba z para una proporción. Al 5%, ¿cuál es la decisión y conclusión correctas?

Sección: Intervalos de confianza¿Cuál es la interpretación correcta de un intervalo de confianza del 95% para la media?

A professor wants to estimate the percentage of students who pass a stat class. Based on the previous experience, the professor guesses that about 80% will pass the class. How many students must be sampled to estimate the true population proportion within 5% with 95% confidence? 

Listening 5 (4 points) Question: Choose the phone number.

Sección: Pruebas de hipótesis: mediaEn el contexto de la prueba de hipótesis anterior, ¿cuál es la interpretación correcta del valor-p?

A local candy shop found from the past observations that 25% of the people who enter the shop actually buy something. Four potential customers enter the shop (you may assume they are independent). Find the probability of at least one sale to the four customers.  

State whether below statement is either a True or a False statement. If it is false, explain why. Please note that you can say something is true if it’s always true. Tensile strength tests were carried out on two different grades of wire rod resulting in the accompanying data.  Based on our “rule of thumb”, we can use the pooled estimate of the standard error. Grade Sample size Sample mean (Kg/mm2) Sample std.dev 1064 19 108 1.3 1078 11 124 1.6    

For each of the following, select the correct answer from the dropdown menu.  If A and B are mutually exclusive events, then P(A) + P(B) = 1. This is a [fill1] statement.  If A and B are independent events, then

Find the following numerical values. (a)