---
title: "R Notebook"
output:
  pdf_document: default
  html_notebook: default
---


```{r}
pnorm(0.5)
```
```{r}
log(2)/87.7
sqrt(0.7)
```

```{r}
log(200)/4*20^2
```
```{r}
(pnorm(-19.5/5)-pnorm(-20.5/5))*2^100
dbinom(30,100,.5)*2^100
```

```{r}
pbinom(30,100,.5)
```

```{r}
qnorm(0.975)
```

```{r}
#x = c(0.96, -0.34, 0.85, 0.51, -0.24)

x = c(8.47, 10.91, 10.87, 9.46, 10.40)
mean(x)
sum((x-mean(x))^2)/4
var(x)
```

```{r}
mean(x)-1.96*sd(x)/sqrt(5)
mean(x)+1.96*sd(x)/sqrt(5)
```

```{r}
z=qt(0.975,4); z
mean(x)-z*sd(x)/sqrt(5)
mean(x)+z*sd(x)/sqrt(5)
```