A simple random sample of n (shown on right) observations from a normally distributed population with a known standard deviation of σ (shown on right), compute the margin of error with (1 - α)100% confidence (α shown on right) associated with a two tailed confidence interval. ROUND THE t or Z STATISTIC OFF TO 2 DECIMAL PLACES [1.645 rounds off to 1.64]
n = 16
σ = 2
α = 0.05
In order to estimate the mean 30-year fixed mortgage rate for a home loan in the United States, a random sample of n (shown on right) recent loans is taken. The average calculated from this sample is (shown on right). It can be assumed that 30-year fixed mortgage rates are normally distributed with a known standard deviation of σ (shown on right). If you were to compute a (1-α)100% two tailed confidence interval for the population mean 30-year fixed mortgage rate, what is the upper confidence limit (UCL)?
n = 64
σ = 4
α = 0.05
x(bar) = 30
Suppose the 95% two tailed confidence interval for the mean grade on the statistics final (shown on right) for n students (on right) at a business college is given on the right. What was the value of the sample mean?
UCL = 95
LCL = 75
n = 64
A random sample of n (shown on right) business students was taken from a normal population with unknown standard deviation resulting in a sample mean, x(bar) (shown on right,) and sample standard deviation, s (shown on right). What would the Margin of Error be for a (1-α)100% [ α is shown on right] two tailed confidence interval be? ROUND THE t or Z STATISTIC OFF TO 2 DECIMAL PLACES [1.645 rounds off to 1.64].
n = 49
s = 4
α = 0.1
X(bar) = 20
A business student is interested in estimating the proportion of students who use cell phones during lectures in the college of business within + B (the Margin of Error) with (1-α)100% (α shown on right) confidence. A casual look around his class indicates that approximately p proportion (shown on right) of his classmates appear to be using cell phones during his class today. How large of a sample should he take? ROUND THE t or Z STATISTIC OFF TO 2 DECIMAL PLACES [1.645 rounds off to 1.64].
B = 0.06
p = 0.2
α = 0.05
An analyst from an energy research institute in California wishes to precisely estimate the (1-α)100% (α shown on right) confidence interval for the average price of unleaded gasoline in the state. In particular, she does not want the sample mean to deviate from the population mean by more than + B dollars. What is the minimum number of gas stations that she should include in her sample if she uses the standard deviation estimate of s dollara, as reported in the popular press?ROUND THE t or Z STATISTIC OFF TO 2 DECIMAL PLACES [1.645 rounds off to 1.64].
B = 0.04
s = 0.22
α = 0.01
A machine set up to fill a single dose of medication used in eye surgery is programmed to put an average of µo ml. (shown on right) in each dose. In order to validate that the machine has been programmed correctly, a random sample of n (shown on right) doses was taken at the start of a production run resulting in a sample mean, X(bar) (shown on right), and sample standard deviation, s (shown on right). If the Null Hypothesis for a two tailed test is Ho: µx = µo what would the sample value of the "standardized test statistic (t or z)" be if the level of significance is α (shown on right).
n = 81
s = 3
X(bar) = 48
Ho: µx = µo = 47
α = 0.1